# include <iostream.h>
int prim (int n)
{  int x=n+1, ok=0, i;
 while(ok==0)
 { int nr=0;
    for(i=2;i<=x/2;i++)
		  if (x%i==0)
			  nr++;
	if(nr==0)
		ok=1;
	else
		x++;
 }
 return x;
}
 int main()
 {  int a;
  cin>>a;
  cout<< prim (a);
  return 0;
  
 }