#include <iostream>
#include <vector>
#include <cmath>

using namespace std;

int main(){
    int n, x[2], i, j;
    float ans[2] = {};
    vector<int> k;

    cin >> n >> x[0] >> x[1];

    for(i=0; i<=n; i++){
        cin >> j;
        k.push_back(j);
    }

    for(i=0; i<2; i++){
        for(j=n; j>=0; j--){
            ans[i] += (float)k[j] / (j + 1) * pow(x[i], j + 1);
        }
    }

    cout << (int)ans[1] - ans[0] << endl;

}