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.Diagnostics;
using System.Globalization;
using System.IO.Pipes;
using System.Runtime;

namespace Csharponly
{
    class Program
    {
        static public void Main()
        {
            int K = Oneint();
		int[] AB = Arrayint();

		string ans = "OK";
		if((AB[0]-1)/K == AB[1]/K )
		{
			ans = "NG";
		}
		
		Console.WriteLine(ans);

        }

　　　　//一つの文字列を受け渡す
        static string Onestring()
        {
            return Console.ReadLine();
        }

        //複数の文字列を配列で受け渡す
        //文字列と文字列の間は" "で区切る
        static string[] Arraystring()
        {
            return Console.ReadLine().Split(' ');
        }

        //一つの数字を受け渡す
        static int Oneint()
        {
            return int.Parse(Console.ReadLine());
        }

        //複数の数字を配列で受け渡す
        //数字と数字の間は" "で区切る
        static int[] Arrayint()
        {
            String[] input_line = Console.ReadLine().Split(' ');
            int[] input_num = new int[input_line.Length];
            for (int i = 0; i < input_line.Length; i++)
            {
                input_num[i] = int.Parse(input_line[i]);
            }
            return input_num;
        }
    }
}