#include "bits/stdc++.h"
#pragma GCC optimize("O3")
#pragma GCC target("arch=corei7-avx")
using namespace std;
 
#define int long long
#define FOR(i, a, b) for (int i = (a), _##i = (b); i <= _##i; ++i)
#define FORD(i, a, b) for (int i = (a), _##i = (b); i >= _##i; --i)
#define REP(i, a) for (int i = 0, _##i = (a); i < _##i; ++i)
#define REPD(i,n) for(int i = (n)-1; i >= 0; --i)
 
#define DEBUG(X) { auto _X = (X); cerr << "L" << __LINE__ << ": " << #X << " = " << (_X) << endl; }
#define PR(A, n) { cerr << "L" << __LINE__ << ": " << #A << " = "; FOR(_, 1, n) cerr << A[_] << ' '; cerr << endl; }
#define PR0(A, n) { cerr << "L" << __LINE__ << ": " << #A << " = "; REP(_, n) cerr << A[_] << ' '; cerr << endl; }
 
#define sqr(x) ((x) * (x))
#define ll long long
// On CF, GNU C++ seems to have some precision issues with long double?
// #define double long double
typedef pair<int, int> II;
#define __builtin_popcount __builtin_popcountll
#define SZ(x) ((int)(x).size())
#define ALL(a) (a).begin(), (a).end()
#define MS(a,x) memset(a, x, sizeof(a))
#define next ackjalscjaowjico
#define prev ajcsoua0wucckjsl
#define y1 alkscj9u20cjeijc
#define left lajcljascjljl
#define right aucouasocjolkjl
#define y0 u9cqu3jioajc
 
#define TWO(X) (1LL<<(X))
#define CONTAIN(S,X) (((S) >> (X)) & 1)
 
long long rand16() {
    return rand() & (TWO(16) - 1);
}
long long my_rand() {
    return rand16() << 32 | rand16() << 16 | rand16();
}
 
// Source: https://github.com/dacin21/dacin21_codebook/blob/master/flow/mincost_PRonly.cpp
//
// Notes:
// - Index from 0
// - Costs multiplied by N --> overflow when big cost?
//
// Tested:
// - https://www.infoarena.ro/problema/fmcm
 
template<typename flow_t = int, typename cost_t = int>
struct MinCostFlow {
    struct Edge {
        cost_t c;
        flow_t f;
        int to, rev;
        Edge(int _to, cost_t _c, flow_t _f, int _rev) : c(_c), f(_f), to(_to), rev(_rev) {}
    };
 
    int N, S, T;
    vector<vector<Edge> > G;
    MinCostFlow(int _N, int _S, int _T) : N(_N), S(_S), T(_T), G(_N), eps(0) {}
 
    void addEdge(int a, int b, flow_t cap, cost_t cost) {
        assert(cap >= 0);
        assert(a >= 0 && a < N && b >= 0 && b < N);
        if (a == b) { assert(cost >= 0); return; }
        cost *= N;
        eps = max(eps, abs(cost));
        G[a].emplace_back(b, cost, cap, G[b].size());
        G[b].emplace_back(a, -cost, 0, G[a].size() - 1);
    }
 
    flow_t getFlow(Edge const &e) {
        return G[e.to][e.rev].f;
    }
 
    pair<flow_t, cost_t> minCostMaxFlow() {
        cost_t retCost = 0;
        for (int i = 0; i<N; ++i) {
            for (Edge &e : G[i]) {
                retCost += e.c*(e.f);
            }
        }
        //find max-flow
        flow_t retFlow = max_flow();
        h.assign(N, 0); ex.assign(N, 0);
        isq.assign(N, 0); cur.assign(N, 0);
        queue<int> q;
        for (; eps; eps >>= scale) {
            //refine
            fill(cur.begin(), cur.end(), 0);
            for (int i = 0; i < N; ++i) {
                for (auto &e : G[i]) {
                    if (h[i] + e.c - h[e.to] < 0 && e.f) push(e, e.f);
                }
            }
            for (int i = 0; i < N; ++i) {
                if (ex[i] > 0){
                    q.push(i);
                    isq[i] = 1;
                }
            }
            // make flow feasible
            while (!q.empty()) {
                int u = q.front(); q.pop();
                isq[u]=0;
                while (ex[u] > 0) {
                    if (cur[u] == G[u].size()) {
                        relabel(u);
                    }
                    for (unsigned int &i=cur[u], max_i = G[u].size(); i < max_i; ++i) {
                        Edge &e = G[u][i];
                        if (h[u] + e.c - h[e.to] < 0) {
                            push(e, ex[u]);
                            if (ex[e.to] > 0 && isq[e.to] == 0) {
                                q.push(e.to);
                                isq[e.to] = 1;
                            }
                            if (ex[u] == 0) break;
                        }
                    }
                }
            }
            if (eps > 1 && eps>>scale == 0) {
                eps = 1<<scale;
            }
        }
        for (int i = 0; i < N; ++i) {
            for (Edge &e : G[i]) {
                retCost -= e.c*(e.f);
            }
        }
        return make_pair(retFlow, retCost / 2 / N);
    }
 
private:
    static constexpr cost_t INFCOST = numeric_limits<cost_t>::max()/2;
    static constexpr int scale = 2;
 
    cost_t eps;
    vector<unsigned int> isq, cur;
    vector<flow_t> ex;
    vector<cost_t> h;
    vector<vector<int> > hs;
    vector<int> co;
 
    void add_flow(Edge& e, flow_t f) {
        Edge &back = G[e.to][e.rev];
        if (!ex[e.to] && f) {
            hs[h[e.to]].push_back(e.to);
        }
        e.f -= f; ex[e.to] += f;
        back.f += f; ex[back.to] -= f;
    }
 
    void push(Edge &e, flow_t amt) {
        if (e.f < amt) amt = e.f;
        e.f -= amt; ex[e.to] += amt;
        G[e.to][e.rev].f += amt; ex[G[e.to][e.rev].to] -= amt;
    }
 
    void relabel(int vertex){
        cost_t newHeight = -INFCOST;
        for (unsigned int i = 0; i < G[vertex].size(); ++i){
            Edge const&e = G[vertex][i];
            if(e.f && newHeight < h[e.to] - e.c){
                newHeight = h[e.to] - e.c;
                cur[vertex] = i;
            }
        }
        h[vertex] = newHeight - eps;
    }
 
    flow_t max_flow() {
        ex.assign(N, 0);
        h.assign(N, 0); hs.resize(2*N);
        co.assign(2*N, 0); cur.assign(N, 0);
        h[S] = N;
        ex[T] = 1;
        co[0] = N-1;
        for (auto &e : G[S]) {
            add_flow(e, e.f);
        }
        if (hs[0].size()) {
            for (int hi = 0; hi>=0;) {
                int u = hs[hi].back();
                hs[hi].pop_back();
                while (ex[u] > 0) { // discharge u
                    if (cur[u] == G[u].size()) {
                        h[u] = 1e9;
                        for(unsigned int i = 0; i < G[u].size(); ++i) {
                            auto &e = G[u][i];
                            if (e.f && h[u] > h[e.to]+1) {
                                h[u] = h[e.to]+1, cur[u] = i;
                            }
                        }
                        if (++co[h[u]], !--co[hi] && hi < N) {
                            for (int i = 0; i < N; ++i) {
                                if (hi < h[i] && h[i] < N) {
                                    --co[h[i]];
                                    h[i] = N + 1;
                                }
                            }
                        }
                        hi = h[u];
                    } else if (G[u][cur[u]].f && h[u] == h[G[u][cur[u]].to]+1) {
                        add_flow(G[u][cur[u]], min(ex[u], G[u][cur[u]].f));
                    } else {
                        ++cur[u];
                    }
                }
                while (hi>=0 && hs[hi].empty()) {
                    --hi;
                }
            }
        }
        return -ex[S];
    }
};
 
int32_t main() {
    freopen("fmcm.in", "r", stdin);
    freopen("fmcm.out", "w", stdout);
 
    int n, m, s, t; cin >> n >> m >> s >> t;
    MinCostFlow<int,int> flow(n, s-1, t-1);
 
    REP(i,m) {
        int u, v, cap, cost; cin >> u >> v >> cap >> cost;
        flow.addEdge(u-1, v-1, cap, cost);
    }
    auto res = flow.minCostMaxFlow();
    cout << res.second << endl;
    return 0;
}