#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int main(){
	ll N,M,K; cin >> N >> M >> K;
	vector<ll> in(N),out(N);
	for(ll i = 0; i < M; i++){
		ll a,b; cin >> a >> b; a--; b--;
		in[b]++; out[a]++;
	}
	
	ll ans = 0, cnt = 0;
	vector<ll> A;
	for(ll i = 0; i < N; i++){
		if(out[i]){
			cnt++;
			ans += max(K - in[i], 0ll);
		}
		else{
			A.push_back(max(K - in[i], 0ll));
		}
	}
	
	sort(A.begin(),A.end());
	for(ll i = 0; i + cnt <= K; i++) ans += A[i];
	cout << ans << "\n";
}