#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int main() {
    int n,a,b;
    cin>>n>>a>>b;
    vector<int> k(n+1);
    for (int i = 0; i <= n; i++)
    {
        cin>>k[i];
    }
    
    double ans=0;
    for (int i = 0; i <= n; i++)
    {
        ans+=(pow(b,i+1)-pow(a,i+1))*k[i]/(i+1);
    }
    
    cout<<floor(ans)<<endl;
}