#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
using mint = modint998244353;
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vll = vector<ll>;
using vvll = vector<vll>;
using vvvll = vector<vvll>;
using vmi = vector<mint>;
using vvmi = vector<vmi>;
using vvvmi = vector<vvmi>;
using vb = vector<bool>;
using vvb = vector<vb>;
using vvvb = vector<vvb>;
#define all(a) (a).begin(), (a).end()
#define rep2(i, m, n) for (int i = (m); i < (n); ++i)
#define rep(i, n) rep2(i, 0, n)
#define drep2(i, m, n) for (int i = (m)-1; i >= (n); --i)
#define drep(i, n) drep2(i, n, 0)

vvb mat(vvb &a, vvb &b, int n){
    vvb res(n, vb(n));
 
    rep(i, n)rep(j, n){
        rep(k, n)res[i][j] = res[i][j] || (a[i][k] && b[k][j]);
    }
    return res;
    
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int n, m; ll t; cin >> n >> m >> t;
    vvb B(n, vb(n, false));
    rep(i, m){
        int a, b; cin >> a >> b;
        B[b][a] = true;
    }

    vvvb bb(64);
    bb[0] = B;
    rep2(i, 1, 64){
        bb[i] = mat(bb[i-1], bb[i-1], n);
    }

    bitset<64> bs(t);
    vvb e(n, vb(n, false)); rep(i, n)e[i][i] = true;
    rep(i, 64){
        if(bs[i])e = mat(e, bb[i], n);
    }
    vb x0(n, false); x0[0] = true;
    int ans = 0;
    rep(i, n){
        bool t = false;
        rep(j, n)t = t || (e[i][j] && x0[j]);
        ans += t;
    }cout << ans << endl;

    return 0;
}