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# (Mono-mcs 6.8.0.105) (judge verdict: Accepted)


using System;
using System.Linq;

namespace AtCoder_165
{
    class Program
    {
        static void Main(string[] args)
        {
            var K = int.Parse(Console.ReadLine());
            var input = Console.ReadLine().Split(' ').Select(s => int.Parse(s)).ToList();
            int a = input[0];
            int b = input[1];

            int cnt = 0;
            bool isOK = false;
            while (true) 
            {
                int i = K * cnt;
                cnt++;

                if (a <= i && i <= b)
                {
                    isOK = true;
                    break;
                }

                if (i > b) break;
            }

            if(isOK) Console.WriteLine("OK");
            else Console.WriteLine("NG");
        }
    }
}