#include <bits/stdc++.h>

using namespace std;

bool viz[305];
int a[305], b[305];
vector<int> g[305];

bool cuplaj(int nod)
{
    if(viz[nod]) return false;
    viz[nod] = true;
    for(int i = 0; i < g[nod].size(); i++)
    {
        if(b[g[nod][i]] == 0)
        {
            b[g[nod][i]] = nod;
            a[nod] = g[nod][i];
            return true;
        }
    }
    for(int i = 0; i < g[nod].size(); i++)
    {
        if(cuplaj(b[g[nod][i]]))
        {
            b[g[nod][i]] = nod;
            a[nod] = g[nod][i];
            return true;
        }
    }
    return false;
}

int main()
{
    freopen("cmcm.in", "r", stdin);
    freopen("cmcm.out", "w", stdout);
    int n, m, e, x, y;
    scanf("%d%d%d", &n, &m, &e);
    for(int i = 0; i < e; i++)
    {
        scanf("%d%d", &x, &y);
        g[x].push_back(y);
    }
    bool dif;
    do
    {
        dif = false;
        memset(viz, 0, sizeof(viz));
        for(int i = 1; i <= n; i++)
        {
            if(a[i] == 0)
                if(cuplaj(i))
                    dif = true;
        }
    } while(dif);
    int rez = 0;
    for(int i = 1; i <= n; i++)
        if(a[i] != 0)
            rez++;
    printf("%d\n", rez);
    for(int i = 1; i <= n; i++)
        if(a[i] != 0)
            printf("%d %d\n", i, a[i]);
    return 0;
}