#include <bits/stdc++.h>
using namespace std;
long long n,m,k,arr[1000000],ans,sum;
int main(){
cin>>n>>m>>k;
for(int i=1;i<=n;i++){
cin>>arr[i];
}
sort(arr+1,arr+1+n,greater<int>());
bool flag=false;
for(int i=1;;i+=m){
if(flag){
break;
}
if(i>=(n-m)){
flag=true;
}
sum=0;
if(!flag){
for(int j=i;j<=i+m;j++){
sum+=arr[j];
}
}else{
for(int j=i;j<=n;j++){
sum+=arr[j];
}
}
if(sum>k){
ans+=k;
}else{
ans+=sum;
}
}
cout<<ans;
}
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