#include <iostream>
#include <vector>
#include <cstring>
#include <fstream>
#include <queue>

using namespace std;

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

const int INF = 1e9 + 9;
const int dim = 2005;

vector <int> vec[dim];

int parent[dim],viz[dim],c[dim][dim],n,m,a[dim],initial[dim][dim],suma,k,e;

int BFS(int sursa,int destinatie)
{
    memset(viz,0,sizeof(viz));
    queue<pair<int,int> > q;
    q.push({sursa, INF});
    viz[sursa] = 1;
    while (!q.empty())
    {
        pair<int,int> x = q.front();
        int flow = x.second;
        q.pop();
        for (int j=0; j<vec[x.first].size(); j++)
        {
            int y = vec[x.first][j];
            if (!viz[y] && c[x.first][y] > 0)
            {
                viz[y] = 1;
                flow = min(flow, c[x.first][y]);
                parent[y] = x.first;
                q.push({y, flow});

                if (y == destinatie) return flow;
            }
        }
    }
    return 0;
}

int Get_Flux(int sursa,int destinatie)
{
    int maxflow = 0;
    int flow = 0;
    int ok;
    while ((flow = BFS(sursa, destinatie)))
    {
        maxflow += flow;
        int x = destinatie;
        while (x != sursa)
        {
            int p = parent[x];
            c[parent[x]][x] -= flow;
            c[x][parent[x]] += flow;
            x = parent[x];
        }
    }
    return maxflow;
}

int main()
{
    int x,y;
    in >> n >> m >> e;
    int sursa = 0;
    int destinatie = n + m + 5;
    for (int i=1; i<=n; i++)
    {
        vec[sursa].push_back(i);
        vec[i].push_back(sursa);
        c[sursa][i] = 1;
    }
    for (int i=1; i<=m; i++)
    {
        vec[n+i].push_back(destinatie);
        vec[destinatie].push_back(n+i);
        c[n+i][destinatie] = 1;
    }
    while (e--)
    {
        in >> x >> y;
        vec[x].push_back(n + y);
        vec[n+y].push_back(x);
        c[x][n+y] = 1;
    }

    out << Get_Flux(sursa, destinatie) << "\n";
    for (int i=1; i<=n; i++)
    {
        for (auto y:vec[i])
        {
            if (c[i][y] == 0 && y > n)
            {
                out << i << " " << y-n << "\n";
            }
        }
    }
    return 0;
}