No tag edit access

A. Panoramix's Prediction

time limit per test

2 secondsmemory limit per test

256 megabytesinput

standard inputoutput

standard outputA 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

Codeforces (c) Copyright 2010-2017 Mike Mirzayanov

The only programming contests Web 2.0 platform

Server time: Jun/24/2017 20:26:40 (c2).

Desktop version, switch to mobile version.

User lists

Name |
---|