#include <iostream>
#include <deque>
#include <vector>
#include <cstring>
#include <bitset>
#include <algorithm>
#define INF 1000010
#define uint unsigned int
#define ll long long
#define split 10000
using namespace std;

int N, M, E, x, y, i, j, sol, cuplat[20010], viz[20010], ok;
vector<int> V[20010];

int DFS(int X)
{
    if(viz[X])
        return 0;
    viz[X] = 1;
    for(vector<int>::iterator it = V[X].begin(); it!=V[X].end(); it++)
    {
        if(!cuplat[*it])
        {
            cuplat[*it] = X;
            cuplat[X] = *it;
            return 1;
        }
    }
    for(vector<int>::iterator it = V[X].begin(); it!=V[X].end(); it++)
    {
        if(DFS(cuplat[*it]))
        {
            cuplat[*it] = X;
            cuplat[X] = *it;
            return 1;
        }
    }
    return 0;
}


int main()
{
    freopen("cuplaj.in","r",stdin);
    freopen("cuplaj.out","w",stdout);
    scanf("%d%d%d", &N, &M, &E);
    while(E--)
    {
        scanf("%d%d", &x, &y);
        V[x].push_back(split + y);
        V[split+y].push_back(x);
    }
    ok = 1;
    while(ok)
    {
        ok = 0;
        memset(viz, 0, sizeof(viz));
        for(i = 1; i <= N; i++)
            if(!viz[i] && !cuplat[i])
                if(DFS(i))
                {
                    ok = 1;
                    sol = sol + 1;
                }
    }
    printf("%d\n", sol);
    for(i=1;i<=N;i++)
        if(cuplat[i])
            printf("%d %d\n", i, cuplat[i]-split);
    return 0;
}