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)

//https://atcoder.jp/contests/abc165/tasks/abc165_a
#include <stdio.h>

int main() {
    
    int a, b, k, i;

    scanf("%d", &k);
    printf("\n");
    
    scanf("%d %d", &a, &b);
    
    if(b-a+1>k||b-a+1==k||k==1)
        printf("OK");
    else{
        for(i=0; i<b-a+2; i++){
            a= a+i;
            if(a%k==0)
                break;
        }
        if(i<b-a+1)
            printf("OK");
        else
            printf("NG");
    }
    
    return 0;
}