#include<bits/stdc++.h>
using namespace std;
const int N=55;
int n;
double k;
double ans;
double c[N];
int main(){
cin>>n>>k;
double cc=1;
c[0]=1;
for(int i=1;i<=n;i++)
{
cc*=(1+k);
c[i]=cc;
}
cin>>ans;
for(int i=1;i<=n;i++){
double x;
cin>>x;
if(x<0){
ans-=(abs(x)/c[i]);
}
else{
ans+=(x/c[i]);
}
}
cout<<fixed<<setprecision(3)<<ans<<endl;
return 0;
}