#include <iostream>
#include <queue>
#include <vector>
#include <algorithm>

using namespace std;

typedef int ll;
typedef pair<ll, int> pli;

const ll INF=1e18;
const ll LARGE=1e12;

int n,m;
queue<int> q;
vector<bool> inq;
vector<ll> raw_cap,cap,cost,dis;
vector<int> head,nxt,from,to,pre;

void add(int u, int v, ll f, ll w) {
	nxt.push_back(head[u]);
	head[u]=to.size();
	from.push_back(u);
	to.push_back(v);
	raw_cap.push_back(f);
	cap.push_back(0);
	cost.push_back(w);
}

void add_edge(int u, int v, ll f, ll w) {
	add(u,v,f,w);
	add(v,u,0,-w);
}

void spfa(int s) {
	inq.assign(n+2,false);
	dis.assign(n+2,INF);
	pre.assign(n+2,-1);
	dis[s]=0;
	q.push(s);

	while(!q.empty()) {
		int u=q.front();
		inq[u]=false;
		q.pop();

		for(int i=head[u]; ~i; i=nxt[i]) {
			int v=to[i];
			ll w=cost[i];
			if(cap[i]&&dis[v]>dis[u]+w) {
				dis[v]=dis[u]+w;
				pre[v]=i;
				if(!inq[v]) {
					inq[v]=true;
					q.push(v);
				}
			}
		}
	}
}

void add_one_cap(int id) {
	int u=from[id];
	int v=to[id];
	if(cap[id]) {
		++cap[id];
		return;
	}
	spfa(v);
	if(dis[u]<INF&&dis[u]+cost[id]<0) {
		++cap[id^1];
		while(u!=v) {
			int x=pre[u];
			--cap[x];
			++cap[x^1];
			u=from[x];
		}
	} else
		++cap[id];
}

int main() {
	freopen("fmcm.in","r",stdin);
	freopen("fmcm.out","w",stdout);
	ios::sync_with_stdio(0);
	cin.tie(0);
	int s,t;

	cin>>n>>m>>s>>t;

	head.resize(n+2,-1);

	for(int i=1; i<=m; ++i) {
		ll u,v,f,w;
		cin>>u>>v>>f>>w;
		add_edge(u,v,f,w);
	}

	add_edge(t,s,LARGE,-LARGE);

    for (int i = 1; i <= n; ++i)
    {
        add_edge(n + 1, i, 0, 0);
        cap[to.size() - 2] = 1;
    }

	for(int i=20; i>=0; --i) {
		for(int j=0; j<=m*2+1; ++j)
			cap[j]<<=1;
		for(int j=0; j<=m*2; j+=2) {
			if((raw_cap[j]>>i)&1) {
				add_one_cap(j);
			}
		}
	}

	ll min_cost=0;

	for(int i=0; i<m; ++i)
		min_cost+=cap[i<<1|1]*cost[i<<1];

	cout<<min_cost;

	return 0;
}