Problem:
Score: 100 points

Problem Statement

Takahashi the Jumbo will practice golf.

His objective is to get a carry distance that is a multiple of K, while he can only make a carry distance of between A and B (inclusive).

If he can achieve the objective, print OK; if he cannot, print NG.

Constraints

All values in input are integers.

1 \leq A \leq B \leq 1000

1 \leq K \leq 1000

Input

Input is given from Standard Input in the following format:

K
A B

Output

If he can achieve the objective, print OK; if he cannot, print NG.

Sample Input 1

7
500 600

Sample Output 1

OK

Among the multiples of 7, for example, 567 lies between 500 and 600.

Sample Input 2

4
5 7

Sample Output 2

NG

No multiple of 4 lies between 5 and 7.

Sample Input 3

1
11 11

Sample Output 3

OK

Solution in C (GCC 9.2.1) (judge verdict: Wrong Answer)

#include <stdio.h>

int main(){

  int k,a,b;
  int x;
  int end=0;
  
  scanf("%d", &k);
  scanf("5d %d", &a, &b);
  
  for(int i = 0; ; i++){
    x = k * i;
    if(a <= x && x <= b){
      end = 1;
      break;
    }
    if(x > b){
      end = 0;
      break;
    }
  }
  if(end == 1){
    printf("OK");
  }else if(end == 0){
    printf("NG");
  }
}