#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)

int main() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    ll n, m, k;
    cin >> n >> m >> k;
    vector<ll> in(n), out(n);
    rep(i, m) {
        int u, v;
        cin >> u >> v;
        u--;
        v--;
        out[u]++;
        in[v]++;
    }
    ll ans = 0;
    int c = 0;
    vector<ll> a;
    rep(i, n) {
        if (out[i] > 0) {
            ans += max(0LL, k - in[i]);
            c++;
        } else {
            a.push_back(max(0LL, k - in[i]));
        }
    }
    sort(a.begin(), a.end());
    rep(i, k + 1 - c) {
        ans += a[i];
    }
    cout << ans << endl;
    return 0;
}