#include <fstream>
#include <vector>
#include <cstring>
using namespace std;

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

const int NMax = 10005;
int N,M,E,Cuplaj;
int L[NMax],R[NMax],Use[NMax];
vector <int> G[NMax];

void Read()
{
  fin >> N >> M >> E;
  for(int i = 1; i <= E; ++i)
    {
      int x,y;
      fin >> x >> y;
      G[x].push_back(y);
    }
}

int Pairup(int Nod)
{
  if(Use[Nod])
    return 0;
  Use[Nod] = 1;

  for(int i = 0; i < (int)G[Nod].size(); ++i)
    {
      int Vecin = G[Nod][i];
      if(!R[Vecin])
        {
          L[Nod] = Vecin;
          R[Vecin] = Nod;
          return 1;
        }
    }
  for(int i = 0; i < (int)G[Nod].size(); ++i)
    {
      int Vecin = G[Nod][i];
      if(Pairup(R[Vecin]))
        {
          L[Nod] = Vecin;
          R[Vecin] = Nod;
          return 1;
        }
    }
  return 0;
}

void Solve()
{
  for(int i = 1; i <= N; ++i)
    {
      if (!L[i])
        {
          memset(Use,0,sizeof(Use));
          Cuplaj += Pairup(i);
        }
    }
}

void Print()
{
  fout << Cuplaj << "\n";
  for(int i = 1; i <= N; ++i)
    if(L[i])
      {
        fout << i << " " << L[i] << "\n";
      }
}

int main()
{
    Read();
    Solve();
    Print();
    return 0;
}