#include <bits/stdc++.h>
using namespace std;
#define repl(i, l, r) for (ll i = (l); i < (r); i++)
#define rep(i, n) repl(i, 0, n)
#define CST(x) cout << fixed << setprecision(x)
using ll = long long;
constexpr ll MOD = 1000000007;
constexpr int inf = 1e9 + 10;
constexpr ll INF = (ll)4e18 + 10;
constexpr int dx[9] = {1, 0, -1, 0, 1, -1, -1, 1, 0};
constexpr int dy[9] = {0, 1, 0, -1, 1, 1, -1, -1, 0};
template <typename T>
inline bool chmax(T &a, T b) {
    return ((a < b) ? (a = b, true) : (false));
}
template <typename T>
inline bool chmin(T &a, T b) {
    return ((a > b) ? (a = b, true) : (false));
}
vector<vector<ll>> product(const vector<vector<ll>> &a, const vector<vector<ll>> &b) {
    assert(a[0].size() == b.size());
    vector<vector<ll>> c(a.size(), vector<ll>(b[0].size()));
    rep(i, (int)a.size()) rep(k, (int)b.size()) rep(j, (int)b[0].size()) {
        c[i][j] = c[i][j] | (a[i][k] & b[k][j]);
    }
    return c;
}
vector<vector<ll>> powmat(vector<vector<ll>> a, ll n) {
    vector<vector<ll>> b(a.size(), vector<ll>(a.size()));
    rep(i, (int)a.size()) b[i][i] = 1;
    while (n > 0) {
        if (n & 1) b = product(b, a);
        a = product(a, a);
        n >>= 1;
    }
    return b;
}
int main() {
    cin.tie(0);
    cout.tie(0);
    ios::sync_with_stdio(false);

    int n, m;
    cin >> n >> m;
    vector<vector<ll>> a(n, vector<ll>(n));
    ll k;
    cin >> k;
    rep(i, m) {
        int x, y;
        cin >> x >> y;
        a[x][y] = 1;
    }
    vector<vector<ll>> ans = powmat(a, k);
    int x = 0;
    rep(i, n) {
        int y = 0;
        rep(j, n) y += ans[i][j];
        x += (y != 0);
    }
    cout << x << endl;
    return 0;
}