#include <bits/stdc++.h>

using namespace std;

using pii = pair<int, int>;
using ll = long long;
const int N = 2000010, MOD = 998244353, INF = 0x3f3f3f3f;
int n, m, w[N];

int f[N], d[N], c, k;
void solve() {
    scanf("%d%d%d", &n, &m, &k);
    for (int i = 1, a, b; i < m + 1; i++) {
        scanf("%d%d", &a, &b);
        f[a] = 1, d[b]++;
    }
    priority_queue<int, vector<int>, greater<int> > q;
    ll res = 0;
    for (int i = 1; i < n + 1; i++)
        if (f[i]) res += max(0, k - d[i]), c++;
        else q.push(max(0, k - d[i]));
    while (c < k + 1) {
        res += q.top(); q.pop();
        c++;
    }
    printf("%lld\n", res);
}

int main() {
    int T = 1;
    // scanf("%d", &T);
    while (T--) solve();
    return 0;
}