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.