A prime number is a number which has exactly two distinct divisors: one and itself. For example, numbers 2, 7, 3 are prime, and 1, 6, 4 are not.

The next prime number after x is the smallest prime number greater than x. For example, the next prime number after 2 is 3, and the next prime number after 3 is 5. Note that there is exactly one next prime number after each number. So 5 is not the next prime number for 2.

One cold April morning Panoramix predicted that soon Kakofonix will break free from his straitjacket, and this will be a black day for the residents of the Gallic countryside.

Panoramix's prophecy tells that if some day Asterix and Obelix beat exactly x Roman soldiers, where x is a prime number, and next day they beat exactly y Roman soldiers, where y is the next prime number after x, then it's time to wait for Armageddon, for nothing can shut Kakofonix up while he sings his infernal song.

Yesterday the Gauls beat n Roman soldiers and it turned out that the number n was prime! Today their victims were a troop of m Romans (m > n). Determine whether the Gauls should wait for the black day after today's victory of Asterix and Obelix?

Input

The first and only input line contains two positive integers — n and m (2 ≤ n < m ≤ 50). It is guaranteed that n is prime.

Pretests contain all the cases with restrictions 2 ≤ n < m ≤ 4.

Output

Print YES, if m is the next prime number after n, or NO otherwise.

Examples

Input

3 5


Output

YES

Input

7 11


Output

YES

Input

7 9


Output

NO
#include <bits/stdc++.h>
int isprime(int x) {
  if (x < 2 || (x % 2 == 0 && x != 2)) return 0;
  int d;
  for (d = 3; d * d <= x; d += 2)
    if (x % d == 0) return 0;
  return 1;
}
int main() {
  int x, y;
  scanf("%d %d", &x, &y);
  int cnt = 0;
  int p = y;
  while (y > x) {
    if (!(isprime(p))) {
      printf("NO\n");
      return 0;
    }
    if (isprime(y)) cnt++;
    y -= 2;
  }
  if (cnt > 1)
    printf("NO\n");
  else
    printf("YES\n");
}
