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

using namespace std;

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

int n, m, e,flow= 0,fmin;
vector<vector<int>> listaAd, capacitate, flux;
vector<int> viz,tata;

bool bf(){
    queue<int> coada;
    coada.push(0);
    for(int i =1;i<=n+m+1;i++)
        viz[i] = 0;
    viz[0] = 1;

    while(!coada.empty()){
        int nod = coada.front();
        coada.pop();
        if(nod == n+m+1) continue;

        for(auto vec:listaAd[nod]){
            if(capacitate[nod][vec]==flux[nod][vec] || viz[vec]) continue;

            viz[vec] = 1;
            coada.push(vec);
            tata[vec] = nod;
        }
    }
    if(viz[n+m+1]==1) return true;
    return false;
}

int main() {
    f >> n >> m >> e;

    listaAd.resize(n + m + 2);
    viz.resize(n+m+2);
    tata.resize(n+m+2);
    vector<int> aux(n + m + 2, 0);
    capacitate.clear();
    capacitate.resize(n + m + 2, aux);
    flux.clear();
    flux.resize(n + m + 2, aux);

    for (int i = 1; i <= e; i++) {
        int x, y;
        f >> x >> y;
        y += n;
        listaAd[x].push_back(y);
        listaAd[y].push_back(x);
        listaAd[0].push_back(x);
        listaAd[x].push_back(0);
        listaAd[y].push_back(n + m + 1);
        listaAd[n+m+1].push_back(y);

        capacitate[x][y] = 1;
        capacitate[0][x] = 1;
        capacitate[y][n + m + 1] = 1;
    }

    vector<pair<int,int>>sol;
    while(bf()){
        for(auto vec:listaAd[n+m+1]){
            if(capacitate[vec][n+m+1]==flux[vec][n+m+1] || !viz[vec])continue;
            tata[n+m+1] = vec;

            fmin = 1e9;
            int nod = n+m+1;

            while(nod!=0){
                fmin = min(fmin,capacitate[tata[nod]][nod]-flux[tata[nod]][nod]);
                nod = tata[nod];
            }

            if(fmin == 0) continue;

            nod = n+m+1;
            int nod1 = tata[nod],nod2;
            while(nod!=0){
                flux[tata[nod]][nod] += fmin;
                flux[nod][tata[nod]] -= fmin;
                if(tata[nod]==0)
                    nod2 = nod;
                nod = tata[nod];

            }

            sol.push_back(make_pair(nod2,nod1-n));
            flow+=fmin;
        }
    }

    g<<flow<<"\n";
    for(auto it: sol){
        g<<it.first<<" "<<it.second<<"\n";
    }
    return 0;

}