#include<iostream>
#include<string>
#include<vector>
using namespace std;

long long bignum = 1000;

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