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 = 0;
	int a = 0;
	int b = 0;
	int i;
	int y = 0;

	scanf("%d\n", &k);
	scanf("%d%d", &a, &b);
	
	//printf("k=%d, a=%d, b=%d \n", k, a, b);


	for(i=1; i<=1000; i++) {
		y = k * i;
		//printf("%d\n", y);
		if(y >= a && y <= b) {
			printf("OK");
			break;
		}
	}

	if(i==1001) {
		printf("NG");
	}

	return 0;
}