#include<stdio.h>
    int main(){
     int K,SA,SB;
      int A,B;
      
      scanf("%d",&K);
      scanf("%d",&A);
      scanf("%d",&B);

      SA=K/A;
      SB=K/B;
      if(SA==SB){
        printf("%s","NG");
      } else {
        printf("%s","OK");
      }
   
      return 0;
    }