#include <iostream>
#include <cmath>
using namespace std;
int main(void){
    int n;
    long double a,b,sum=0;
    cin>>n>>a>>b;
    n++;
    long double k[n];
    for(int i=0;i<n;i++){
        cin>>k[i];
        sum+=k[i]*pow(b,i+1)/(i+1);
        sum-=k[i]*pow(a,i+1)/(i+1);
    }
    cout<<(long long)sum<<endl;
    return 0;
}