//
// Created by zeronosu77108 on Jan 15, 2021.
//
#include <iostream>
#include <iomanip>
#include <vector>
#include <utility>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <algorithm>
#include <queue>
#include <cmath>
#include <numeric>
#include <set>
#include <complex>
#include <optional>

using namespace std;
struct aaa{aaa(){cin.tie(nullptr); ios::sync_with_stdio(false); cout<<fixed<<setprecision(20);};}aaa;
template <class T>ostream &operator<<(ostream &o,const vector<T>&v){o<<"{";for(int i=0;i<(int)v.size();i++)o<<(i>0?", ":"")<<v[i];o<<"}";return o;}
#define debug(v) {cerr<<"\033[1;36m[debug]\033[m "<<#v<<" : "<<(v)<<endl;}

using int64 = long long;

int main() {
    int n, m;
    long t;
    cin >> n >> m >> t;


    long z = 64 - __builtin_clzl(t);
    vector d(z+10, vector(n+10, unordered_set<int>()));

    for (int i=0; i<m; i++) {
        int a, b;
        cin >> a >> b;
        d[0][a].insert(b);
    }


    for (int i=0; i<z; i++) {
        for (int j=0; j<n; j++) {
            for (const auto& v : d[i][j]) {
                for (const auto& u : d[i][v]) d[i+1][j].insert(u);
            }
        }
    }

    unordered_set<int> ans = {0};

    for (int i=0; i<=z; i++) {
        if (t&1) {
           unordered_set<int> next;
            for (const auto& v : ans) {
                for (const auto& u : d[i][v]) next.insert(u);
            }
            swap(ans, next);
        }
        t/=2;
    }

    cout << ans.size() << endl;
}