#include<stdio.h>
int main()
{
  int a,b,k,n;
  scanf("%d %d %d",&k,&a,&b);
  while(b>=a){
    a=a+1;
    a++;
    if(n%k==0){
      if(a<=n<=b){
      break;
      printf("OK\n");
      }
      else{
        printf("NG\n");
      }
    }
    else{
      printf("NG\n");
    }
  }
  return 0;
}