#include <fstream>
#include <vector>
#include <queue>

using namespace std;

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

using VI = vector<int>;
using VVI = vector<VI>;
using VB = vector<bool>;

#define inf 10000000

int n, m, n1, n2;
VVI G, c, f;
VI dad;

bool bfs()
{
    queue<int> Q;
    Q.push(0);
    VB viz = VB(n + 2);
    int node, V;
    while (!Q.empty())
    {
        node = Q.front();
        Q.pop();
        if (node == n + 1)return 1;
        for (int i = 0; i < G[node].size(); ++ i)
        {
            V = G[node][i];
            if (viz[V] || c[node][V] == f[node][V])continue;
            viz[V] = 1;
            dad[V] = node;
            Q.push(V);
        }
    }
    return 0;
}
int main()
{
    cin >> n1 >> n2 >> m;
    n = n1 + n2;
    G = VVI(n + 2);
    c = VVI(n + 2, VI(n + 2));
    f = VVI(n + 2, VI(n + 2));
    dad = VI(n + 2);

    int x, y;
    while (m --)
    {
        cin >> x >> y;
        G[x].push_back(y + n1);
        G[y + n1].push_back(x);
        c[x][y + n1] ++;
    }

    for (int i = 1; i <= n1; ++ i)
    {
        G[0].push_back(i);
        G[i].push_back(0);
        c[0][i] = 1;
    }
    for (int i = 1; i <= n2; ++ i)
    {
        G[n + 1].push_back(n1 + i);
        G[n1 + i].push_back(n + 1);
        c[n1 + i][n + 1] = 1;
    }

    int V, flow = 0, val;
    while (bfs())
        for (int i = 0; i < G[n + 1].size(); ++ i)
        {
            V = G[n + 1][i];
            if (f[V][n + 1] == c[V][n + 1])continue;
            dad[n + 1] = V;

            val = inf;
            for (int j = n + 1; j != 0; j = dad[j])
                val = min(val, c[dad[j]][j] - f[dad[j]][j]);

            if (val)
                for (int j = n + 1; j != 0; j = dad[j])
                {
                    f[dad[j]][j] += val;
                    f[j][dad[j]] -= val;
                }
            flow += val;
        }
    cout << flow << '\n';
    for (int i = 1; i <= n1; ++ i)
        for (int j = 0; j < G[i].size(); ++ j)
            if (f[i][G[i][j]] && G[i][j] > n1)
                cout << i << ' ' << G[i][j] - n1  << '\n';
    return 0;
}