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: Accepted)

#include<stdio.h>

int main(void){
	int K,A,B,comp;
	
	scanf("%d",&K);
	scanf("%d %d",&A,&B);
	
	int worst = A/K;
	int best = B/K;
	
	while(1){
		comp = K*worst;
		if(A <= comp && comp <= B){
			printf("OK\n");
			break;
		}else if(comp < A){
			worst++;
		}else{
			printf("NG\n");
			break;
		}
	}
	
	
	return 0;
}