#include <bits/stdc++.h>
using namespace std;
vector<vector<bool>> matrix_multiplication(vector<vector<bool>> A, vector<vector<bool>> B){
  int N = A.size();
  vector<vector<bool>> C(N, vector<bool>(N, false));
  for (int i = 0; i < N; i++){
    for (int j = 0; j < N; j++){
      for (int k = 0; k < N; k++){
        if (A[i][j] && B[j][k]){
          C[i][k] = true;
        }
      }
    }
  }
  return C;
}
vector<vector<bool>> matrix_exponentiation(vector<vector<bool>> A, long long x){
  int N = A.size();
  vector<vector<bool>> ans(N, vector<bool>(N, false));
  for (int i = 0; i < N; i++){
    ans[i][i] = true;
  }
  while (x > 0){
    if (x % 2 == 1){
      ans = matrix_multiplication(ans, A);
    }
    A = matrix_multiplication(A, A);
    x /= 2;
  }
  return ans;
}
int main(){
  int N, M;
  long long T;
  cin >> N >> M >> T;
  vector<vector<bool>> E(N, vector<bool>(N, false));
  for (int i = 0; i < M; i++){
    int a, b;
    cin >> a >> b;
    E[a][b] = true;
  }
  E = matrix_exponentiation(E, T);
  int ans = 0;
  for (int i = 0; i < N; i++){
    if (E[0][i]){
      ans++;
    }
  }
  cout << ans << endl;
}