#include<bits/stdc++.h>
// #include<atcoder/all>

using namespace std;
// using namespace atcoder;
using ll = long long;
using ull = unsigned long long;
using P = pair<int,int>;
#define rep(i,n) for(ll i = 0;i < (ll)n;i++)
#define ALL(x) (x).begin(),(x).end()
#define MOD 1000000007


// 2020/12/31
void matrix_mul(vector<vector<bool>> &v,vector<vector<bool>> &w){
  int n = v.size(),m = w[0].size(),l = w.size();
  vector<vector<bool>> res(n,vector<bool>(m));
  for(int i = 0;i < n;i++)for(int j = 0;j < m;j++){
    bool k = 0;
    for(int g = 0;g < l;g++)k |= (v[i][g] && w[g][j]);
    res[i][j] = k;
  }
  swap(res,v);
}

//正方行列のみだよ
void matrix_pow(vector<vector<bool>> &v,ll K){
  int n = v.size();
  vector<vector<bool>> res(n,vector<bool>(n,1));
  while(K){
    if(K & 1)matrix_mul(res,v);
    matrix_mul(v,v);
    K >>= 1;
  }
  swap(res,v);
}

int main(){
  
  ll n,m,T;
  cin >> n >> m >> T;
  vector<vector<bool>> v(n,vector<bool>(n,0));
  rep(i,m){
    int a,b;cin >> a >> b;
    v[b][a] = 1;
  }
  matrix_pow(v,T);
  vector<vector<bool>> res(n,vector<bool>(1,0));
  res[0][0] = 1;
  matrix_mul(v,res);
  int ans = 0;
  rep(i,n)if(v[i][0])ans++;
  cout << ans << "\n";

  

  return 0;
}