#include <bits/stdc++.h>
using namespace std;
int n,m,k,arr[10000000],ans;
int main(){
cin>>n>>m>>k;
for(int i=1;i<=n;i++){
cin>>arr[i];
}
for(int i=1;i<=n;i+=m){
long long sum=0;
for(int j=i;j<=i+m;j++){
sum+=arr[j];
}
if(sum<=k){
ans+=sum;
}else{
ans+=k;
}
}
cout<<ans;
}
I2luY2x1ZGUgPGJpdHMvc3RkYysrLmg+CnVzaW5nIG5hbWVzcGFjZSBzdGQ7CmludCBuLG0sayxhcnJbMTAwMDAwMDBdLGFuczsKaW50IG1haW4oKXsKCWNpbj4+bj4+bT4+azsKCWZvcihpbnQgaT0xO2k8PW47aSsrKXsKCQljaW4+PmFycltpXTsKCX0KCWZvcihpbnQgaT0xO2k8PW47aSs9bSl7CgkJbG9uZyBsb25nIHN1bT0wOwoJCWZvcihpbnQgaj1pO2o8PWkrbTtqKyspewoJCQlzdW0rPWFycltqXTsKCQl9CgkJaWYoc3VtPD1rKXsKCQkJYW5zKz1zdW07CgkJfWVsc2V7CgkJCWFucys9azsKCQl9Cgl9Cgljb3V0PDxhbnM7Cn0=