#include<bits/stdc++.h>
using namespace std;

const int NMAX=10005;
vector<int> G[NMAX];

int n,ans;
int st[NMAX],dr[NMAX],viz[NMAX];

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

void solve(){
    bool gata=0;
    while(!gata){
        gata=1;
        for(int i=1;i<=n;i++)
            viz[i]=0;
        for(int i=1;i<=n;i++)
            if(!st[i] && cupleaza(i)){
                ans++;
                gata=0;
            }
    }
}

int main(){
    freopen("cuplaj.in","r",stdin);
    freopen("cuplaj.out","w",stdout);
    int m,e;
    scanf("%d%d%d", &n, &m, &e);
    while(e--){
        int x,y;
        scanf("%d%d", &x, &y);
        G[x].push_back(y);
    }
    solve();
    printf("%d\n", ans);
    for(int i=1;i<=n;i++)
        if(st[i])
            printf("%d %d\n", i, st[i]);
    return 0;
}