#include <iostream>
#include <algorithm>
#include <iomanip>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <cassert>

#define debug_value(x) cerr << "line" << __LINE__ << ":<" << __func__ << ">:" << #x << "=" << x << endl;
#define debug(x) cerr << "line" << __LINE__ << ":<" << __func__ << ">:" << x << endl;

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; }

using namespace std;
typedef long long ll;

class Bit{
    public:
    bool v;
    Bit(bool _v = false){
        v = _v;
    }
    Bit operator+(bool b){
        return Bit(v|b);
    }
    Bit operator*(bool b){
        return Bit(v&b);
    }

    void operator+=(bool b){
        v |= b;
    }
    void operator*=(bool b){
        v &= b;
    }
    
    
    Bit operator+(Bit b){
        return Bit(v|b.v);
    }
    Bit operator*(Bit b){
        return Bit(v&b.v);
    }

    void operator+=(Bit b){
        v |= b.v;
    }
    void operator*=(Bit b){
        v &= b.v;
    }
};


template <typename T>
struct matrix{
    int n, m;
    vector<vector<T>> dat;
    matrix(int n_, int m_){
        n = n_; m = m_;
        for(int i = 0; i < n; i++){
            dat.push_back(vector<T>(m));
        }
    }
    vector<T>& operator[](int x) {
        return dat[x];
	}
};

template <typename T>
bool prod(matrix<T> a, matrix<T> b, matrix<T> &ans){
    assert(a.m == b.n);
    for(int i = 0; i < a.n; i++){
        for(int j = 0; j < b.m; j++){
            ans.dat[i][j] = 0;
            for(int k = 0; k < b.n; k++){
                ans.dat[i][j] += (a.dat[i][k]*b.dat[k][j]);
            }
        }
    }
    return true;
}

template <typename T>
void copy_mat(matrix<T> a, matrix<T> &b){
    assert(a.n == b.n);
    assert(a.m == b.m);
    for(int i = 0; i < a.n; i++){
        for(int j = 0; j < a.m; j++){
            b.dat[i][j] = a.dat[i][j];
        }
    }
}

template <typename T>
void pow_mat(matrix<T> a, ll n, matrix<T> &ans){
    assert(n < ((ll)1<<61));
    matrix<T> buf(a.n, a.n);
    matrix<T> tmp(a.n, a.n);
    copy_mat(a, tmp);

    for(int i = 0; i < a.n; i++) {
        for(int j = 0; j < a.n; j++){
            ans.dat[i][j] = 0;
        }
        ans.dat[i][i] = 1;
    }
    
    for(int i = 0; i <= 60; i++){
        ll m = (ll)1 << i;
        if(m&n){
            prod(tmp, ans, buf);
            copy_mat(buf, ans);
        }
        prod(tmp, tmp, buf);
        copy_mat(buf, tmp);
    }
}

int n, m;
ll t;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << setprecision(10) << fixed;
    cin >> n >> m >> t;
    matrix<Bit> mat(n, n);
    for(int i = 0; i < m; i++){
        int a, b; cin >> a >> b;
        mat[b][a] = true;
    }
    matrix<Bit> v(n, 1);
    v[0][0] = true;
    matrix<Bit> pw(n, n);
    pow_mat(mat, t, pw);
    matrix<Bit> ans(n, 1);
    prod(pw, v, ans);
    // cout << ans << endl;
    int sum = 0;
    for(int i = 0; i < n; i++) {
        if(ans[i][0].v) sum++;
    }
    cout << sum << endl;
}