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>
#include <string.h>

int main(void)
{
    int k,a,b;
    int flag=0;

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

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

    if (flag==1)
        printf("OK");
    else
        printf("NG");
    
    return 0;
    

}