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

using namespace std;


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

int L,R,m,x,y,n,S,T;
vector<vector<int>> flux;
vector<vector<int>> C;
vector<vector<int>> adj;
vector<int> tata;

bool gaseste_lant_nesaturat(){
    queue<int> q;
    vector<int> visited(n+2,0);
    fill(tata.begin(), tata.end(), 0);

    q.push(0);
    tata[0] = 0;
    visited[0] = 1;

    while(!q.empty()){
        int nod = q.front();
        q.pop();

        for(auto& neigh: adj[nod]){
            if(visited[neigh] == 0 && C[nod][neigh] > flux[nod][neigh]){
                q.push(neigh);
                visited[neigh] = 1;
                tata[neigh] = nod;
                if(neigh == T){
                    return true;
                }
            }
            if(visited[neigh] == 0 && flux[neigh][nod] > 0){
                q.push(neigh);
                visited[neigh] = 1;
                tata[neigh] = -nod;
                if(neigh == T){
                    return true;
                }
            }
        }
    }
    return false;


}

int main(){

    f >> L >> R >> m;

    n = L + R;
    S = 0;
    T = n+1;

    flux.assign(T + 1, vector<int>(T + 1, 0));
    C.assign(T + 1, vector<int>(T + 1, 0));

    adj.resize(n+2);
    tata.resize(n+2);

    for(int i=1; i<=m; i++){
        f >> x >> y;

        int nod_stanga = x;
        int nod_dreapta = y+L;

        if(C[S][nod_stanga] == 0){
            adj[S].push_back(nod_stanga);
            adj[nod_stanga].push_back(S);
            C[S][nod_stanga] = 1;
        }

        adj[nod_stanga].push_back(nod_dreapta);
        adj[nod_dreapta].push_back(nod_stanga);
        C[nod_stanga][nod_dreapta] = 1;

        if(C[nod_dreapta][T] == 0){
            adj[nod_dreapta].push_back(T);
            adj[T].push_back(nod_dreapta);
            C[nod_dreapta][T] = 1;
        }
    }

    int flux_maxim = 0;

    while(gaseste_lant_nesaturat()){
        
        for(int v = T; v!=S;){
            int u = tata[v];
            
            if(u >= 0){
                flux[u][v] = 1;
                v = u;
            }
            else{
                int real_u = -u;
                flux[v][real_u] = 0;
                v = real_u;
            }
        }
        flux_maxim += 1;
    }

    g << flux_maxim << '\n';

    for(int i=1; i<=n; i++){
        for(auto& neigh: adj[i]){
            if(neigh > L && neigh <= L+R){
                if(flux[i][neigh] == 1){
                    g << i << " " << neigh-L << "\n";
                }
            }
        }
    }


    return 0;
}