using System;
using System.Numerics;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Formats.Asn1;
using System.Globalization;
using System.Linq;

namespace algorism
{
    class Program
    {
        static void Main()
        {
            string[] input1 = Console.ReadLine().Split(" ");
            int N = int.Parse(input1[0]);
            int A = int.Parse(input1[1]);
            int B = int.Parse(input1[2]);

            BigInteger temp = 0;
            BigInteger factorial = 1;

            // factorial = (N+1)!
            for (int i = 1; i <= N + 1; i++) factorial *= i;

            for (int i = 0; i < N + 1; i++)
            {
                BigInteger nanika = BigInteger.Parse(Console.ReadLine());
                BigInteger kaijyou = factorial / (i + 1);
                BigInteger diff = BigInteger.Pow(B, i + 1) - BigInteger.Pow(A, i + 1);
                temp += diff * nanika * kaijyou;
            }

            // ↓ floor除算で切り捨て
            BigInteger ans = FloorDiv(temp, factorial);
            Console.WriteLine(ans);
        }

        static BigInteger FloorDiv(BigInteger a, BigInteger b)
        {
            if (a >= 0) return a / b;
            else return -(((-a) + b - 1) / b);
        }
    }
}