/* -*- coding: utf-8 -*-
 *
 * 3362.cc:  No.3362 遨榊・!!! - yukicoder
 */

#include<cstdio>
#include<cmath>
#include<algorithm>

using namespace std;

/* constant */

const int MAX_N = 10 + 1;

/* typedef */

using ll = long long;
using ld = long double;

/* global variables */

int ks[MAX_N];

/* subroutines */

ld itgf(int n, int ks[], int x) {
  ld ex = x, sum = 0.0;
  for (int i = 0; i <= n; i++) {
    sum += ks[i] * ex / (i + 1);
    ex *= x;
  }
  return sum;
}

/* main */

int main() {
  int n, a, b;
  scanf("%d%d%d", &n, &a, &b);
  for (int i = 0; i <= n; i++) scanf("%d", ks + i);

  ld x = floorl(itgf(n, ks, b) - itgf(n, ks, a));
  printf("%lld\n", (ll)x);
  
  return 0;
}