#include <bits/stdc++.h>
using namespace std;
#include <boost/multiprecision/cpp_int.hpp>
using namespace boost::multiprecision;

#define rep(i, a, b) for (int i = a; i < b; i++)
using ll = long long;

int main(){
	int n, a, b;
	cin >> n >> a >> b;
	vector<int> k(n + 1);
	rep(i, 0, n + 1) cin >> k[i];
	cpp_int f = 1;
	rep(i, 1, n + 2) f *= i;
	cpp_int s = 0, aa = a, bb = b;
	rep(i, 0, n + 1) {
		s += k[i] * (bb - aa) * (f / (i + 1));
		aa *= a;
		bb *= b;
	}
	cout << s / f << endl;
}