#include<stdio.h>
int main()
{
int a,b,t,i,j;

scanf("%d%d",&a,&b);
if(a>b)
t=a;
a=b;
b=t;
for(i=a;i<=b;i++)
{j=2;
while((i%j)!=0)
{j++;
if(j>=i)
printf("%d",i);}
}
return 0;
}