#include <iostream>
#include <vector>

using namespace std;

int n, m, e, ps[10005], pd[10013];
bool viz[10010];
vector<int> adj[10004];

bool aug (int nod)
{
    if (viz[nod]) return 0;
    viz[nod] = 1;
    for (int i : adj[nod])
    {
        if (pd[i] == 0)
        {
            ps[nod] = i;
            pd[i] = nod;
            return 1;
        }
    }
    for (int i : adj[nod])
    {
        if (aug(pd[i]))
        {
            ps[nod] = i;
            pd[i] = nod;
            return 1;
        }
    }
    return 0;
}

int main ()
{
    freopen("cuplaj.in", "r", stdin);
    freopen("cuplaj.out", "w", stdout);


    cin >> n >> m >> e;
    for (int i = 1; i <= e; i++)
    {
        int a, b; cin >> a >> b;
        adj[a].push_back(b);
    }

    bool check = 1;

    while (check)
    {
        check = 0;
        for (int i = 1; i <= n; i++){
            viz[i] = 0;
        }
        for (int i = 1; i <= n; i++)
        {
            if (ps[i] == 0) check |= aug(i);
        }
    }

    int ans = 0;
    for (int i = 1; i <= n; i++)
    {
        if (ps[i]) ans++;
    }

    cout << ans << '\n';

    for (int i = 1; i <= n; i++)
    {
        if (ps[i]) cout << i << ' ' << ps[i] << '\n';
    }
}