#include <fstream>
#include <vector>
#define VAL 10005

using namespace std;

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

int N, M, E, i, j, A, B;
int L[VAL], R[VAL], ANS;
bool ok[VAL], nemodif;
vector <int> G[VAL];

bool Cuplaj(int nod)
{
    vector <int> :: iterator it;
    int nod2;
    if (ok[nod]==true)
      return false;
    ok[nod]=true;
    for (it=G[nod].begin(); it!=G[nod].end(); it++)
    {
        nod2=*it;
        if (R[nod2]==0)
        {
            L[nod]=nod2;
            R[nod2]=nod;
            ANS++;
            return true;
        }
    }
    for (it=G[nod].begin(); it!=G[nod].end(); it++)
    {
        nod2=*it;
        if (Cuplaj(R[nod2])==true)
        {
            L[nod]=nod2;
            R[nod2]=nod;
            return true;
        }
    }
    return false;
}

int main()
{
    fin >> N >> M >> E;
    for (i=1; i<=E; i++)
    {
        fin >> A >> B;
        G[A].push_back(B);
    }
    while (nemodif==false)
    {
        nemodif=true;
        for (i=1; i<=N; i++)
          ok[i]=false;
        for (i=1; i<=N; i++)
          if (L[i]==0 && Cuplaj(i)==true)
           nemodif=false;
    }
    fout << ANS << '\n';
    for (i=1; i<=N; i++)
      if (L[i]>0)
        fout << i << " " << L[i] << '\n';
    fin.close();
    fout.close();
    return 0;
}