#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
#define rep(i, n) REP(i, 0, n)
#define REP(i, s, e) for (int i = (s); i < (int)(e); i++)
#define repr(i, n) REPR(i, n, 0)
#define REPR(i, s, e) for (int i = (int)(s - 1); i >= (int)(e); i--)
#define all(r) r.begin(), r.end()
#define rall(r) r.rbegin(), r.rend()

typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vl;

template <typename T, typename U>
T chmax(T& a, const T& b) {
    if (a >= b) return false;
    a = b;
    return true;
}
template <typename T, typename U>
T chmin(T& a, const T& b) {
    if (a <= b) return false;
    a = b;
    return true;
}

void yes_no(bool f, string yes = "Yes", string no = "No") { cout << (f ? yes : no) << "\n"; }

void solve() {
    ll n, m, k;
    cin >> n >> m >> k;
    vector<int> in(n), out(n);
    rep(i, m) {
        int a, b;
        cin >> a >> b;
        --a;
        --b;
        out[a]++;
        in[b]++;
    }
    ll x = 0;
    ll cnt = 0;
    priority_queue<ll> q;
    rep(i, n) {
        if (out[i] > 0) {
            x += max(0LL, k - in[i]);
            cnt++;
        } else {
            q.emplace(in[i]);
        }
    }
    while (cnt < k + 1) {
        ll y = q.top();
        q.pop();
        x += max(k - y, 0LL);
        cnt++;
    }
    cout << x << "\n";
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int t = 1;
    // cin >> t;
    rep(ti, t) solve();
    return 0;
}