#include <bits/stdc++.h>
using namespace std;
#define si(a) (long)a.size()
#define fi first
#define se second
#define all(x) x.begin(),x.end()
#define rep(i,n) for(int i=0;i<(int)(n);++i)
template<typename S,typename F>bool chmin(S&a,F b){return b<a?(a=b,1):0;}
template<typename S,typename F>bool chmax(S&a,F b){return b>a?(a=b,1):0;}
bool _=(ios::sync_with_stdio(0),cin.tie(0),cout<<fixed<<setprecision(16),0);


int main(){
    int N,M,K;
    cin>>N>>M>>K;
    vector<int> in(N,0),out(N,0);
    rep(i,M){
        int a,b;
        cin>>a>>b;
        a--;b--;
        out[a]++;
        in[b]++;
    }
    long ans=0;
    int cnt=0;
    rep(i,N)if(out[i]){
        cnt++;
        ans+=max(0,K-in[i]);
    }
    vector<int> A;
    rep(i,N)if(!out[i])A.push_back(in[i]);
    sort(all(A),greater<>());
    rep(i,K+1-cnt)ans+=max(0,K-A[i]);
    cout<<ans<<"\n";
}