#include<iostream>
#include<array>
#include<string>
#include<cstdio>
#include<vector>
#include<cmath>
#include<algorithm>
#include<functional>
#include<iomanip>
#include<queue>
#include<ciso646>
#include<random>
#include<map>
#include<set>
#include<complex>
#include<bitset>
#include<stack>
#include<unordered_map>
#include<utility>
#include<tuple>
#include<cassert>
using namespace std;
typedef long long ll;
typedef unsigned int ui;
const ll mod = 1000000007;
const ll INF = (ll)1000000007 * 1000000007;
typedef pair<int, int> P;
#define stop char nyaa;cin>>nyaa;
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define Rep(i,sta,n) for(int i=sta;i<n;i++)
#define Per(i,sta,n) for(int i=n-1;i>=sta;i--)
#define rep1(i,n) for(int i=1;i<=n;i++)
#define per1(i,n) for(int i=n;i>=1;i--)
#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)
typedef long double ld;
const ld eps = 1e-8;
const ld pi = acos(-1.0);
typedef pair<ll, ll> LP;
int dx[4]={1,-1,0,0};
int dy[4]={0,0,1,-1};
template<class T>bool chmax(T &a, const T &b) {if(a<b){a=b;return 1;}return 0;}
template<class T>bool chmin(T &a, const T &b) {if(b<a){a=b;return 1;}return 0;}

template<typename T>
struct Matrix{
  vector<vector<T>> val;
  Matrix(){}
  Matrix(int n,int m,T x=0):val(n,vector<T>(m,x)){}
  Matrix(vector<vector<T>> a):val(a){}
  size_t size() const {return val.size();}
  inline vector<T>& operator [] (int i) {return val[i];}

  Matrix<T> &operator=(const vector<vector<T>> &A) {
    int n=A.size(),m=A[0].size();
    val=A;
    return *this;
  }

  Matrix<T> &operator+=(const Matrix<T> &A) {
    for (int i=0;i<val.size();++i) 
        for (int j=0;j<val[0].size();++j)
            val[i][j]=val[i][j]+A.val[i][j];   
    return *this;
  }
  Matrix<T> &operator+=(const vector<vector<T>> &A) { return *this += Matrix(A); }

  Matrix<T> &operator-=(const Matrix<T> &A) {
    for (int i=0;i<val.size();++i) 
        for (int j=0;j<val[0].size();++j)
            val[i][j]=val[i][j]-A.val[i][j];   
    return *this;
  }
  Matrix<T> &operator-=(const vector<vector<T>> &A) { return *this -= Matrix(A); }

  Matrix<T> &operator*=(const Matrix<T> &A) {
    Matrix<T> R(val.size(),A.val[0].size());
    for (int i = 0; i < val.size(); ++i) 
        for (int j = 0; j < A.val[0].size(); ++j)
            for (int k = 0; k < A.size(); ++k) 
                R[i][j] = (R[i][j] | (val[i][k] & A.val[k][j])); 
    for (int i=0;i<val.size();++i) 
        for (int j=0;j<val[0].size();++j)
            val[i][j]=R.val[i][j]; 
    return *this;
  }
  Matrix<T> &operator*=(const vector<vector<T>> &A) { return *this *= Matrix(A); }

  Matrix<T> operator+(const Matrix<T> &p) const { return Matrix<T>(*this) += p; }
  Matrix<T> operator-(const Matrix<T> &p) const { return Matrix<T>(*this) -= p; }
  Matrix<T> operator*(const Matrix<T> &p) const { return Matrix<T>(*this) *= p; }

  bool operator==(const Matrix<T> &p) const { return val == p.val; }
  bool operator!=(const Matrix<T> &p) const { return val != p.val; }

  Matrix<T> pow(long long n) {
    Matrix<T> A=*this;
    Matrix<T> R(A.size(), A.size());
    for (int i = 0; i < A.size(); ++i) R[i][i] = 1;
    while (n > 0) {
      if (n & 1) R = R * A;
      A = A * A;
      n >>= 1;
    }
  return R;
  }

};

int n,m;ll t;

void solve(){
    cin >> n >> m >> t;
    Matrix<int> A(n,n),s(n,1);s[0][0]=1;
    rep(i,m){
        int a,b;cin >> a >> b;
        A[b][a]=1;
    }
    Matrix<int> ans=A.pow(t)*s;
    int x=0;
    rep(i,n) if(ans[i][0]==1)x++;
    cout << x << endl;
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << fixed << setprecision(50);
    solve();
}