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
//44,45,47,50,53,54,55
import java.util.*;
import java.io.*;
public class CF80A
{    //*****************************************    VARIABLE DECLERATION SECTION   ********************************************************************;
         //Integer ArrayList Math TreeMap TreeSet
         // System.out.println
         static boolean[] arr;

    //*****************************************    VARIABLE DECLERATION ENDS   ********************************************************************;

    //************************************************   MAIN FUNCTION  *************************************************************************; 
    public static void main(String[] args) 
    {   
         FastReader scan=new FastReader();
        int n=scan.nextInt(),m=scan.nextInt();
        seive(n,m);
    }
    //***********************************************  MAIN FUNCTION ENDS   *********************************************************************;

    //**********************************************   AUXILIARY FUNCTIONS  **********************************************************************;
    static void seive(int n,int m)
    {  arr=new boolean[m+1];
        arr[0]=arr[1]=true;
        for(int i=2;i<=m;i++)
        {
            if(arr[i])continue;
            for(int j=2*i;j<=m;j=j+i)
                arr[j]=true;
        }
        int idx=0;
        for(int i=n+1;i<=m;i++)
        {   if(!arr[i])
            {
                idx=i;break;
            }

        }
        if(idx==m)System.out.println("YES");
        else System.out.println("NO");

    }
    //**********************************************   AUXILIARY FUNCTIONS  ENDS  **********************************************************************;

    //**********************************************   INPUT FUNCTIONS     ******************************************************************************;
       static class FastReader
    {   BufferedReader br;   StringTokenizer st;
        public FastReader()
        {  br = new BufferedReader(new  InputStreamReader(System.in)); }
        String next()
        {    while (st == null || !st.hasMoreElements())
            {    try
                {  st = new StringTokenizer(br.readLine()); }
                catch (IOException  e)
                {  e.printStackTrace(); }
            }
            return st.nextToken();
        }
        int nextInt()
        {   return Integer.parseInt(next()); }
        long nextLong()
        {   return Long.parseLong(next()); }
        double nextDouble()
        {  return Double.parseDouble(next()); }
        String nextLine()
        { String str = "";
            try
            {     str = br.readLine(); }
            catch (IOException e)
            {     e.printStackTrace(); }
            return str;
        }
    }
    //**********************************************   INPUT FUNCTIONS     ******************************************************************************;
}