/**
 *    author:  otera    
**/
#include<bits/stdc++.h>
using namespace std;

#define int long long
typedef long long ll;
typedef long double ld;
const int inf=1e9+7;
const ll INF=1LL<<60;
#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++)
typedef pair<int, int> P;
typedef pair<ll, ll> LP;
#define fr first
#define sc second
#define all(c) c.begin(),c.end()
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }

vector<vector<int>> mul(vector<vector<int>> a, vector<vector<int>> b) {
    int sz = (int)a.size();
    vector<vector<int>> ret(sz, vector<int>(sz, 0));
    rep(i, sz) {
        rep(j, sz) {
            rep(k, sz) {
                ret[i][k] |= (a[i][j] & b[j][k]);
            }
        }
    }
    return ret;
}

vector<vector<int>> pw(vector<vector<int>> a, ll n) {
    int sz = (int)a.size();
    if(n == 0) {
        vector<vector<int>> ret(sz, vector<int>(sz, 0));
        rep(i, sz) {
            ret[i][i] = 1LL;
        }
        return ret;
    }
    vector<vector<int>> ret = pw(mul(a, a), n / 2);
    if(n & 1) ret = mul(ret, a);
    return ret;
}

void solve() {
    int n, m; ll t; cin >> n >> m >> t;
    vector<vector<int>> g(n, vector<int>());
    vector<vector<int>> d(n, vector<int>(n, 0));
    rep(i, m) {
        int a, b; cin >> a >> b;
        g[a].push_back(b);
        d[a][b] = 1;
    }
    d = pw(d, t);
    int cnt = 0;
    rep(i, n) {
        if(d[0][i]) {
            cerr << i << endl;
            ++ cnt;
        }
    }
    cout << cnt << "\n";
}

signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	//cout << fixed << setprecision(20);
	//int t; cin >> t; rep(i, t)solve();
	solve();
    return 0;
}