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 A, B, K;
  int flag = 0;
  int calc = 0;
  
  if (A<1 || A>B || 1000<B){
    printf("NG");

  }
  
  for (int i=1; (i*K)<1000; i++){
    if(A<=i*K && i*K<=B){
      printf("OK");
      flag = 1;
      break;
    }
  }
  
  if(flag == 0){
    printf("NG");
  }
   return 0;
}