#include <iostream>
#include <fstream>
#include <vector>
#define pb push_back
#define nl '\n'
using namespace std;
ifstream f ( "cuplaj.in" );
ofstream g ( "cuplaj.out" );
const int NMAX = 10001;
vector<int>G[NMAX];
int N, M, E, L[NMAX], R[NMAX], maxMatch;
bool viz[NMAX];///nodurile folosite intr-o iteratie
void citire()
{
    int x, y;
    f >> N >> M >> E;

    while ( E-- )
    {
        f >> x >> y;
        G[x].pb ( y );
    }
}
bool match ( int x )
{
    if ( viz[x] )
        return 0;

    viz[x] = 1;

    for ( auto &y : G[x] )
        if ( R[y] == 0 )
        {
            L[x] = y;
            R[y] = x;
            return 1;
        }

    for ( auto &y : G[x] )
        if ( match ( R[y] ) )
        {
            L[x] = y;
            R[y] = x;
            return 1;
        }

    return 0;
}
void HK()
{
    bool wasChanged = 1;
    int i;

    while ( wasChanged )
    {
        wasChanged = 0;

        for ( i = 1; i <= N; i++ )
            viz[i] = 0;

        for ( i = 1; i <= N; i++ )
            if ( !L[i] && match ( i ) )
            {
                wasChanged = 1;
                maxMatch++;
            }
    }
}
int main()
{
    citire();
    HK();
    g << maxMatch << nl;

    for ( int i = 1; i <= N; i++ )
    {
        if ( L[i] != 0 )
            g << i << ' ' << L[i] << nl;
    }

    f.close();
    g.close();
    return 0;
}