#include <iostream> 
#include <fstream> 
#include <vector>

using namespace std; 

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

const int NMAX = 10005;
int n, m, e, sol;
int st[NMAX], dr[NMAX];
bool viz[NMAX];
vector < int > L[NMAX];

void citire()
{
    int x, y;
    fin >> n >> m >> e;
    for(int i = 1; i <= e; i++)
    {
        fin >> x >> y;
        L[x].push_back(y);
    }
}

bool Cuplaj(int nod)
{
    if(viz[nod])
        return false;
    viz[nod] = true;
    for(auto it : L[nod])
    {
        if(!dr[it])
        {
            st[nod] = it;
            dr[it] = nod;
            return true;
        }
    }
    for(auto it : L[nod])
    {
        if(dr[it] && Cuplaj(dr[it]))
        {
            st[nod] = it;
            dr[it] = nod;
            return true;
        }
    }
    return false;
}

void solve()
{
    bool solved = false;
    while (!solved)
    {
        solved = true;
        for(int i = 1; i <= n; i++)
            viz[i] = false;
        for(int i = 1; i <= n; i++)
        {
            if(!st[i] && Cuplaj(i))
            {
                sol++;
                solved = false;
            }
        }
    }
    fout << sol << "\n";
    for(int i = 1; i <= n; i++)
    {
        if(st[i])
            fout << i << " " << st[i] << "\n";
    }
}

int main()
{ 
    citire();
    solve();
    return 0;
}