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# (.NET Core 3.1.201) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;

namespace Atcoder
{
    class Program
    {
        static void Main(string[] args)
        {
            var k = int.Parse(Console.ReadLine());
            var ab = Console.ReadLine().Split().Select(s => int.Parse(s)).ToArray();
            int cnt = 0;
            string ans;
            while (true)
            {
                if(k*cnt >= ab[0] && k * cnt <= ab[1])
                {
                    ans = "OK";
                    break;
                }
                else if(k * cnt > ab[1])
                {
                    ans = "NG";
                    break;
                }
                cnt++;
            }

            Console.WriteLine(ans);

        }
    }
}