#include <stdio.h>

int main(void)
{
  		int K,A,B,n;
  		K = 2;
      	A = 100;
      	B = 900;
      	n = A <= B && n >= A;
	
    if(( n % K ) ==0 )
    {
    	printf("OK");
    }
    else
    {
    	printf("NG");
    }
}