#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); i++)
using namespace std;
typedef long long ll;

vector<vector<long long>> matmul(vector<vector<long long>> A, vector<vector<long long>> B){
   int N = A.size();
   vector<vector<long long>> ans(N, vector<long long>(N, 0));
   for (int i = 0; i < N; i++){
       for (int j = 0; j < N; j++){
           for (int k = 0; k < N; k++){
               ans[i][k] |= A[i][j] & B[j][k];
           }
       }
   }
   return ans;
}
vector<vector<long long>> matpow(vector<vector<long long>> A, long long b){
   int N = A.size();
   vector<vector<long long>> ans(N, vector<long long>(N, 0));
   for (int i = 0; i < N; i++){
       ans[i][i] = 1;
   }
   while (b > 0){
       if (b % 2 == 1){
           ans = matmul(ans, A);
       }
       A = matmul(A, A);
       b /= 2;
   }
   return ans;
}

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);

    ll N,M,T; cin >> N >> M >> T;
    vector<vector<ll>> A(N, vector<ll> (N, 0));
    rep(i,M){
        ll a,b; cin >> a >> b;
        A[a][b] = 1;
    }
    A = matpow(A, T);
    int ans = 0;
    rep(i,N) ans += A[0][i];
    cout << ans << '\n';
}