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
import java.io.*;
import java.util.*;
public class j
{
public static void main(String a[])throws IOException
{
BufferedReader b=new BufferedReader(new InputStreamReader(System.in));
int z=0,g=0,j=0,m=0,n=0,f=0,h=0,i=0;
String s;
s=b.readLine();
StringTokenizer c=new StringTokenizer(s);
m=Integer.parseInt(c.nextToken());
n=Integer.parseInt(c.nextToken());
if(n==4)
System.out.print("NO");
else
{
for(i=2;i<n/2&&n!=4;i++)
if(n%i==0)
{
f=1;
break;
}
if(f==1)
System.out.print("NO");
else
{
for(i=m+1;i<n;i++)
{
if(i==4)
{
h=1;
continue;
}
h=0;
for(j=2;j<i/2;j++)
{
if(i%j==0)
{
g=1;
break;
}
}
if(g==0)
{
z=1;
System.out.print("NO");
break;
}
g=0;
}
if(g==0&&z==0&&i!=5)
System.out.print("YES");
if(h==1)
System.out.print("YES");
}
}
}
}