#include <fstream>
#include <vector>
#include <deque>
#include <bitset>

using namespace std;

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

int n, m, i, nod, crt, tata, minim,sol, t[20002], tatf[20002], e, vecin, ult, x, y, nodmare, nodmic;
char flux[20002][20002], c[20002][20002];
bitset<20002> f;
deque<int> coada;
vector<int> v[20002];

int bfs(){
    f.reset();
    f[0] = 1;
    int ok = 0;
    t[0] = -1;
    coada.push_back(0);
    while(!coada.empty()){
        int nod = coada[0];
        for(int i = 0;i<v[nod].size();i++){
            int vecin = v[nod][i];
            if(f[vecin] == 0 && c[nod][vecin] > flux[nod][vecin]){
                coada.push_back(vecin);
                f[vecin] = 1;
                t[vecin] = nod;
                if(vecin == ult)
                    ok = 1;
            }
        }
        coada.pop_front();
    }
    return ok;
}

int main(){
    fin>>n>>m>>e;
    ult = 2*n+1;
    for(i=1;i<=e;i++){
        fin>>x>>y;
        y += n;
        if(f[y] == 0)
            v[ult].push_back(y);
        f[y] = 1;
        v[0].push_back(x);
        c[0][x] = 1;
        v[x].push_back(0);
        v[x].push_back(y);
        c[x][y] = 1;
        v[y].push_back(x);
        v[y].push_back(ult);
        c[y][ult] = 1;
    }
    while(bfs()){
        for(i=0;i<v[ult].size();i++){
            int crt = v[ult][i];
            if(f[nod] == 1){
                nod = crt;
                tata = t[nod];
                minim = c[nod][ult] - flux[nod][ult];
                while(tata != -1){
                    minim = min(minim, c[tata][nod] - flux[tata][nod]);
                    nod = tata;
                    tata = t[nod];
                }
                nod = ult;
                tata = crt;
                while(tata != -1){
                    flux[tata][nod] += minim;
                    flux[nod][tata] -= minim;
                    nodmare = max(nod, tata);
                    nodmic = min(nod, tata);
                    if(flux[nodmic][nodmare] == 1)
                        tatf[nodmare] = nodmic;

                    nod = tata;
                    tata = t[nod];
                }
                sol += minim;
            }
        }
    }
    fout<<sol<<"\n";
   for(i=0;i<v[ult].size();i++){
        crt = v[ult][i];
        if(flux[crt][ult] == 1)
            fout<<tatf[crt]<<" "<<crt-n<<"\n";

    }
    return 0;
}