#include <iostream>
#include <bits/stdc++.h>

#define maxFlow 1e9

using namespace std;

ifstream in ("cuplaj.in");
ofstream out ("cuplaj.out");

struct hash_pair {
    template <class T1, class T2>
    size_t operator()(const pair<T1, T2>& p) const
    {
        auto hash1 = hash<T1>{}(p.first);
        auto hash2 = hash<T2>{}(p.second);
        return hash1 ^ hash2;
    }
};

int n1, n2;
int n, m;
int s, f;
vector<int> la[20001];
unordered_map<pair<int,int>, int, hash_pair> fluxLeft(20000);
int parent[20001];
int flux = 0;

void getPath()
{
    // fluxLeft.reserve(20000);
    memset(parent, 0, sizeof(parent));
    vector<int> q;
    parent[s] = -1;
    q.push_back(s);

    for (int i = 0; i < q.size() ; i++)
    {
        if (q[i] == n)
        {
            continue;
        }
        for (auto to: la[q[i]])
        {
            if (fluxLeft[{q[i], to}] <= 0 || parent[to] != 0)
                continue;

            parent[to] = q[i];
            q.push_back(to);
        }
    }
}

int main()
{
    in >> n1 >> n2 >> m;
    n = n1 + n2 + 2;
    s = 1; f = n;
    for (int i = 1; i <= m ; ++i)
    {
        int x,y;
        in >> x >> y;
        x += 1;
        y += 1 + n1;
        la[x].push_back(y);
        la[y].push_back(x);

        fluxLeft[{x,y}] = 1;
    }

    // muchii de la start la nodurile din stanga
    for (int i = 2; i <= n1+1; i++)
    {
        la[1].push_back(i);
        la[i].push_back(1);
        fluxLeft[{1, i}] = 1;
    }
    // muchii de la nodurile din dreapta la final
    for (int i = n1 + 2; i <= n1 + 1 + n2; i++)
    {
        la[i].push_back(n1 + n2 + 2);
        la[n1 + n2 + 2].push_back(i);
        fluxLeft[{i, n1 + n2 + 2}] = 1;
    }

    getPath();
    while (parent[f] != 0)
    {
        for (int i = -1; i < (int)la[f].size(); i++)
        {
            if (i != -1)
            {
                parent[f] = la[f][i];
            }

            int minn = maxFlow;
            int nod = f;
            while (parent[nod] != -1)
            {
                if (fluxLeft[{parent[nod], nod}] < minn)
                    minn = fluxLeft[{parent[nod], nod}];
                if (minn <= 0)
                    break;
                nod = parent[nod];
            }

            if (minn <= 0)
                continue;

            flux += minn;
            nod = f;
            while (parent[nod] != -1)
            {
                fluxLeft[{parent[nod], nod}] -= minn;
                fluxLeft[{nod, parent[nod]}] += minn;
                nod = parent[nod];
            }
        }

        getPath();
    }

    out << flux << '\n';

    for (int i = 2; i < 2 + n1; i++)
    {
        for (auto to: la[i])
        {
            if (to == 1)
                continue;
            if (fluxLeft[{i, to}] == 0)
                out << i-1 << ' ' << to - 1 - n1 << '\n';
        }
    }

    return 0;
}

/*
6 8
1 2 10
1 3 8
2 3 2
2 4 5
3 5 10
5 4 8
4 6 7
5 6 10
// 15
*/

/*
6 7
1 2 6
1 3 8
2 4 5
3 5 4
2 5 3
4 6 7
5 6 5
// 10
*/