#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<ll,ll> P;
#define REP(i,n) for(ll i=0;i<ll(n);i++)









int main(void){
	cin.tie(nullptr);  ios_base::sync_with_stdio(false);
	ll i,j;





	ll N;
	ll A,B;
	cin >> N >> A >> B;

	vector<ll> a(N+2,1);
	vector<ll> b(N+2,1);

	for(i=1;i<=N+1;i++) a[i]=A*a[i-1];
	for(i=1;i<=N+1;i++) b[i]=B*b[i-1];


	double ans=0;
	for(i=1;i<=N+1;i++){

		ll K;
		cin >> K;

		ll d=K*(b[i]-a[i]);
		double dd=1.0*d/i;

		ans+=dd;


	}



	cout << (ll)ans << endl;








	return 0;

}