botanics

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

namespace Q10408
{
    class Program
    {
        static private int _n, _q; static private bool ntof, qtof; static private string[] sarr; static private double[] darr;
        static private string[] sarr2; static private double[] darr2;
        static void Main(string[] args)
        {
            for (; ; )
            {
            labeln: Console.Write("N>>>");
                ntof = int.TryParse(Console.ReadLine(), out _n);
                if (!ntof) goto labeln;
                sarr = new string[(int)(_n * _n * 0.4)]; darr = new double[(int)(_n * _n * 0.4)];
                int count = 1; darr[0] = 1; sarr[0] = "1/1";
                for (int i = 1; i <= _n; i++)
                    for (int j = 1; j <= i; j++)
                        if (GCD(i, j)) { darr[count] = (double)j / (double)i; sarr[count] = j + "/" + i; count++; }
                int amount = 0; foreach (double obj in darr) amount += obj == 0 ? 0 : 1;
                sarr2 = new string[amount]; darr2 = new double[amount];
                amount = 0;
                for (int i = 0; i < sarr.Length; i++)
                {
                    if (darr[i] != 0)
                    {
                        darr2[amount] = darr[i]; sarr2[amount] = sarr[i]; amount++;
                    }
                }
                Array.Sort(darr2, sarr2);
            labelq: Console.Write("Question>>>");
                qtof = int.TryParse(Console.ReadLine(), out _q);
                if (!qtof) goto labelq;
                Console.WriteLine("Ans={0}", sarr2[_q - 1]);
            }
        }
        static public bool GCD(int x, int y)
        {
            while (true)
            {
                if (x > y) x = x % y;
                else if (x < y) y = y % x;
                else { return false; }
                if (x == 1 || y == 1) { return true; }
                else if (x == 0 || y == 0) { return false; }
            }
        }
    }
}