#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#include <unordered_set>
#include <climits>

using namespace std;

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

int n,m,e;
int N;
vector<int> E[10003];
int L[10003];
int R[10003];
bool u[10003];

bool pairup(int nod) {

    if(u[nod])
        return 0;
    u[nod] = 1;
    //cout << nod << " " << L[nod] << '\n';

    for(int i = 0; i < E[nod].size(); i++) {
        if(R[E[nod][i]] == 0) {
            L[nod] = E[nod][i];
            R[E[nod][i]] = nod;
            return 1;
        }
    }

    for(int i = 0; i < E[nod].size(); i++) {
        if(R[E[nod][i]] != nod && pairup(R[E[nod][i]])) {
            L[nod] = E[nod][i];
            R[E[nod][i]] = nod;
            return 1;
        }
    }

    return 0;

}

int main() {

    in >> n >> m >> e;
    int x,y;

    for(int i = 1; i <= e; i++) {
        in >> x >> y;
        E[x].push_back(y);
    }

    int cup = 0;

    for(int i = 1; i <= n; i++)  {
        for(int j = 1; j <= n; j++)
            u[j] = 0;
        if(L[i] != 0)
            continue;
        cup += pairup(i);
    }

    out << cup << '\n';

    for(int i = 1; i <= n; i++) {
        if(L[i] == 0)
            continue;
        out << i << " " << L[i] << '\n';
    }

    return 0;
}