/* -*- coding: utf-8 -*-
 *
 * 1340.cc:  No.1340 おーじ君をさがせ - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int MAX_N = 100;

/* typedef */

typedef long long ll;
typedef bool vec[MAX_N];
typedef vec mat[MAX_N];

/* global variables */

mat ma, mb;

/* subroutines */

inline void initmat(const int n, mat a) { memset(a, 0, sizeof(mat)); }

inline void unitmat(const int n, mat a) {
  initmat(n, a);
  for (int i = 0; i < n; i++) a[i][i] = true;
}

inline void copymat(const int n, const mat a, mat b) {
  memcpy(b, a, sizeof(mat));
}

inline void mulmat(const int n, const mat a, const mat b, mat c) {
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++) {
      c[i][j] = false;
      for (int k = 0; k < n; k++)
        c[i][j] |= (a[i][k] & b[k][j]);
    }
}

inline void powmat(const int n, const mat a, ll b, mat c) {
  mat s, t;
  copymat(n, a, s);
  unitmat(n, c);

  while (b > 0) {
    if (b & 1) {
      mulmat(n, c, s, t);
      copymat(n, t, c);
    }

    mulmat(n, s, s, t);
    copymat(n, t, s);
    b >>= 1;
  }
}

/* subroutines */

/* main */

int main() {
  int n, m;
  ll t;
  scanf("%d%d%lld", &n, &m, &t);

  initmat(n, ma);
  while (m--) {
    int a, b;
    scanf("%d%d", &a, &b);
    ma[a][b] = true;
  }

  powmat(n, ma, t, mb);

  int c = 0;
  for (int i = 0; i < n; i++)
    if (mb[0][i]) c++;
  printf("%d\n", c);
  return 0;
}