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

int main() {
    int n;
    int a,b;
    cin>>n>>a>>b;
    vector<ll> k(n+1);
    for (int i = 0; i <= n; i++)
    {
        cin>>k[i];
    }

    ll sum=0;
    ll mul=1;
    for (int i = 0; i <= n; i++)
    {
        mul*=(i+1);
    }

    for (int i = 0; i <= n; i++)
    {
        sum+=(b-a)*k[i]*mul/(i+1);
        a*=a;
        b*=b;
    }
    
    cout<<sum/mul<<endl;
}