#include <cstdio>
#include <vector>
#include <bitset>

#define Nmax 10005

using namespace std;

vector <int> G[Nmax];
bitset <Nmax> Viz;

int N, M, E, Nr;
int L[Nmax], R[Nmax];

void Citire()
{
    int x, y;

    scanf("%d %d %d", &N, &M, &E);

    for (int i = 1; i <= E; ++i)
    {
        scanf("%d %d", &x, &y);
        G[x].push_back(y);
    }
}

bool Cuplaj(int nod)
{
    vector <int> :: iterator it;

    if (Viz[nod])
        return false;

    Viz[nod] = 1;

    for (it = G[nod].begin(); it != G[nod].end(); ++it)
    {
        if (!R[*it] || Cuplaj(R[*it]))
        {
            L[nod] = *it;
            R[*it] = nod;
            return true;
        }
    }

    return false;
}

void Rezolvare()
{
    int ok = 1;

    while (ok)
    {
        ok = 0;
        Viz = 0;
        for (int i = 1; i <= N; ++i)
            if (!L[i] && Cuplaj(i))
            {
                ok = 1;
                Nr++;
            }
    }
}

void Afisare()
{
    printf("%d\n", Nr);

    for (int i = 1; i <= N; ++i)
        if (L[i] != 0)
            printf("%d %d\n", i, L[i]);
}

int main()
{
    freopen("cuplaj.in", "r", stdin);
    freopen("cuplaj.out", "w", stdout);

    Citire();
    Rezolvare();
    Afisare();

    return 0;
}