#include <bits/stdc++.h>
const int NMAX = 1e3; 
std::vector<int> Ladj[NMAX + 1];
int L[NMAX + 1][NMAX + 1];
int flux[NMAX + 1][NMAX + 1];
int vis[NMAX + 1];
int n, m;
int p[NMAX + 1];
int bfs(int s, int dest)
{
    for (int i = 0; i <= n + m + 1; i++)
    {
        vis[i] = 0;
        p[i] = 0;
    }
    std::queue<int> q;
    q.push(s);

    vis[s] = 1;
    while (!q.empty())
    {
        int nod = q.front();
        q.pop();
        for (auto vecin : Ladj[nod])
        {
            if (!vis[vecin] && L[nod][vecin] - flux[nod][vecin] > 0)
            {
                vis[vecin] = 1;
                p[vecin] = nod;
                q.push(vecin);
            }
        }
    }
    if (!vis[dest])
    {
        return 0;
    }
    std::vector<int> path;
    int x = dest;
    while (x != 0)
    {
        path.push_back(x);
        x = p[x];
        if (x == s) {
            path.push_back(x);
            break;
        }
    }
    std::reverse(path.begin(), path.end());
    int flow = 1e9;
    for (int i = 0; i < path.size() - 1; i++)
    {
        int a = path[i];
        int b = path[i + 1];
        flow = std::min(flow, L[a][b] - flux[a][b]);
    }
    for (int i = 0; i < path.size() - 1; i++)
    {
        int a = path[i];
        int b = path[i + 1];
        flux[a][b] += flow;
        flux[b][a] -= flow;
    }
    return flow;
}

int main()
{
    std::ifstream fin("cuplaj.in");
    std::ofstream fout("cuplaj.out");
    int e;
    fin >> n >> m >> e;

    for (int i = 0; i <= n + m + 1; ++i) {
        for (int j = 0; j <= n + m + 1; ++j) {
            L[i][j] = 0;
            flux[i][j] = 0;
        }
    }

    for (int i = 1; i <= e; i++)
    {
        int a, b;
        fin >> a >> b;
        L[a][n + b] = 1;
        Ladj[a].push_back(n + b);
        Ladj[n+b].push_back(a);
    }
    for (int i = 1; i <= n; i++)
    {
        Ladj[0].push_back(i);
        Ladj[i].push_back(0);
        L[0][i] = 1;
    }
    for (int i = n + 1; i <= n + m; i++)
    {
        Ladj[i].push_back(n + m + 1);
        Ladj[n+m+1].push_back(i);
        L[i][n + m + 1] = 1;
    }
    int maxflow = 0;
    while (true)
    {
        int flow = bfs(0, n + m + 1);
        if (flow == 0)
        {
            break;
        }
        maxflow += flow;
    }
    fout << maxflow << std::endl;
    for (int i = 1; i <= n; i++)
    {
        for (int j = n + 1; j <= n + m; j++)
        {
            if (flux[i][j] == 1)
            {
                fout << i << " " << j - n << std::endl;
            }
        }
    }
    fin.close();
    fout.close();
    return 0;
}