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>
using namespace std;
double a, b, c;
double k;
bool possible(int n) {
  int ar[10] = {0};
  int k = 1000;
  for (int i = 0; i < 4; i++) {
    ar[n / k]++;
    if (ar[n / k] > 1) {
      return false;
    }
    n = n % k;
    k = k / 10;
  }
  return true;
}
int main() {
  int primes[51] = {0};
  for (int i = 2; i <= 8; i++) {
    if (primes[i] == 0) {
      primes[i] = 0;
      for (int j = 2 * i; j <= 50; j += i) {
        primes[j] = -1;
      }
    }
  }
  int n, m;
  cin >> n >> m;
  for (int i = n + 1; i <= 50; i++) {
    if (primes[i] == 0) {
      if (i == m) {
        cout << "YES" << endl;
        return 0;
      } else {
        cout << "NO" << endl;
        return 0;
      }
    }
  }
  cout << "NO" << endl;
  return 0;
}
