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.IO;
using System.Linq;
using System.Collections.Generic;
using System.Text;
using System.Numerics;

namespace abc165
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.SetOut(new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false });
            if (File.Exists("input.txt"))
            {
                Console.SetIn(new StreamReader("input.txt"));
            }
            solve_abc165A();
            Console.Out.Flush();
        }

        public static void solve_abc165B()
        {
        }

        public static void solve_abc165A()
        {
            int k = Convert.ToInt32(Console.ReadLine());
            int[] ab = Array.ConvertAll(Console.ReadLine().Split(), int.Parse);
            bool ok = false;
            for (int i = ab[0]; i <= ab[1]; i++)
            {
                if (i % k == 0)
                {
                    ok = true;
                    break;
                }
            }
            Console.WriteLine(ok ? "OK" : "NG");
        }
    }
}