#include <iostream>
using namespace std;
int main() {
// your code goes here
int n,m,k=0,p,k1=0,l;
cin>>n>>m;
for(int i=n;i<=m;i++)
{
p=0,l=0;
for (int j=1;j<=i;j++)
{
if(i>n && i<m)
{
if(i%j==0)
p++;
}
else if(i==n || i==m)
{
if(i%j==0)
l++;
}
}
if(p==2)
k++;
if(l==2)
k1++;
}
if(k1==2 && k==0)
cout<<"YES";
else
cout<<"NO";
}
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