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

using namespace std;

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

const int NMAX = 1001;

vector<vector<int>> edgRezid;
vector<int> tata;
int rezid[NMAX][NMAX];
int n, m, e;

bool BFS(int s, int t)
{
    queue<int> q;
    vector<int> viz(n + m + 2, 0);
    tata.resize(n + m + 2, 0);
    q.push(s);
    while (!q.empty())
    {
        int u = q.front();
        q.pop();
        for (auto &v : edgRezid[u])
        {
            if (!viz[v] && rezid[u][v] > 0)
            {
                viz[v] = 1;
                q.push(v);
                tata[v] = u;
                if (v == t)
                    return true;
            }
        }
    }
    return false;
}

int capRezid(vector<int> &tata, int s, int t)
{
    int mn = 200000;
    for (int v = t; v != s; v = tata[v])
    {
        mn = min(mn, rezid[tata[v]][v]);
    }
    return mn;
}

void actualizareFlux(vector<int> &tata, int s, int t, int cr)
{
    for (int v = t; v != s; v = tata[v])
    {

        rezid[tata[v]][v] -= cr;

        rezid[v][tata[v]] += cr;
    }
}

int main()
{
    fin >> n >> m >> e;
    edgRezid.resize(n + m + 2);
    // edgOut.resize(n+1);
    while (e--)
    {
        int u, v, c;
        fin >> u >> v;
        edgRezid[u].push_back(v + n);
        edgRezid[v + n].push_back(u);
        rezid[u][v + n] = 1;
    }
    int sursa = 0;
    int target = n + m + 1;
    for (int i = 1; i <= n; ++i)
    {
        edgRezid[sursa].push_back(i);
        rezid[sursa][i] = 1;
    }
    for (int i = n + 1; i <= n + m; ++i)
    {
        edgRezid[i].push_back(target);
        rezid[i][target] = 1;
    }
    int fluxmax = 0;
    while (BFS(sursa, target))
    {
        int cr = capRezid(tata, sursa, target);
        actualizareFlux(tata, sursa, target, cr);
        fluxmax += cr;
    }
    fout << fluxmax << "\n";
    for (int i = 1; i <= n; ++i)
    {
        for (int j = n + 1; j <= n + m; ++j)
        {
            if (rezid[j][i] == 1)
                fout << i << " " << j - n << "\n";
        }
    }
    return 0;
}