#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf32 1000000001
#define Inf64 4000000000000000001LL

int main(){
	
	long long N,M,K;
	cin>>N>>M>>K;
	
	vector<long long> x(N),y(N);
	rep(i,M){
		int a,b;
		cin>>a>>b;
		a--,b--;
		x[a] ++;
		y[b] ++;
	}
	
	long long ans = 0;
	long long num = 0;
	vector<long long> cost;
	rep(i,N){
		if(x[i]>0){
			num++;
			ans += max(0LL,K - y[i]);
		}
		else{
			cost.push_back(max(0LL,K - y[i]));
		}
	}
	sort(cost.begin(),cost.end());
	if(num < K+1){
		rep(i,K+1 - num)ans += cost[i];
	}
	cout<<ans<<endl;
	return 0;
}