#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define ALL(v) v.begin(),v.end()
typedef long long ll;

#include <bits/stdc++.h>
using namespace std;

vector<vector<ll>> matrixmul(ll m,vector<vector<ll>> a,vector<vector<ll>> b){
  vector<vector<ll>> c(m,vector<ll>(m,0));
  rep(i,m){
    rep(j,m){
      rep(k,m) c[i][j]=c[i][j]|(a[i][k]&b[k][j]);
    }
  }
  return c;
}

vector<vector<ll>> matrixpow(ll m,vector<vector<ll>> vec,ll n){
  vector<vector<ll>> ans(m,vector<ll>(m,0));
  rep(i,m) ans[i][i]=1;
  while(n){
    if(n&1) ans=matrixmul(m,ans,vec);
    vec=matrixmul(m,vec,vec);
    n>>=1;
  }
  return ans;
}

int main(){
  int n,m;
  ll t;
  cin>>n>>m>>t;
  
  vector<vector<ll>> A(n,vector<ll> (n));
  rep(i,m){
    int a,b;
    cin>>a>>b;
    A[b][a]=1;
  }
  
  vector<vector<ll>> B=matrixpow(n,A,t);
  int ans=0;
  rep(i,n){
    if(B[i][0]==1) ans++;
  }
  cout<<ans<<endl;
  
  return 0;
}