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

namespace Upwards
{
    // A simple Scanner class meant to be similar to java's scanner.
    // Author: Daniel Wasserman
    // Date: 2013-05-30
    class Scanner
    {
        TextReader Reader;
        public Scanner(TextReader reader)
        {
            Reader = reader;
        }

        static int Index = 0;
        static string[] CurrentLine = { };

        public bool HasNext()
        {
            if (CurrentLine.Length == Index)
            {
                try
                {
                    CurrentLine = Reader.ReadLine().Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
                    Index = 0;
                    return HasNext();
                }
                catch (System.IO.IOException e)
                {
                    return false;
                }
            }
            return true;
        }

        public String Next()
        {
            if (HasNext()) return CurrentLine[Index++];
            return null;
        }

        public int NextInt()
        {
            return int.Parse(Next());
        }

        public long NextLong()
        {
            return long.Parse(Next());
        }

        public float NextFloat()
        {
            return float.Parse(Next());
        }

        public double NextDouble()
        {
            return double.Parse(Next());
        }
    }


    class Program
    {
        static int k, n;
        static void Main(string[] args)
        {
            Scanner inp = new Scanner(new StreamReader("upwards.in"));

            int cases = inp.NextInt();
            for (int caseOn = 1; caseOn <= cases; caseOn++)
            {
                k = inp.NextInt();
                n = inp.NextInt();
                long r = inp.NextInt() - 1;

                count = new long[n + 1, 26];
                for (int i = 0; i < count.GetLength(0); i++)
                    for (int j = 0; j < count.GetLength(1); j++)
                        count[i, j] = -1;

                int[] arr = new int[n];
                for (int i = 0; i < n; i++)
                {
                    int letterStart = i == 0 ? 0 : arr[i - 1] + k + 1;
                    while (true)
                    {
                        long cnt = go(i, letterStart);
                        if (cnt > r)
                        {
                            arr[i] = letterStart;
                            break;
                        }
                        r -= cnt;
                        letterStart++;
                    }
                }

                foreach (int a in arr)
                {
                    Console.Write((char)(a + 'a'));
                }
                Console.WriteLine();
            }

        }

        static long[,] count;
        public static long go(int index, int letter)
        {
            if (letter >= 26) return 0;
            if (index == n - 1) return 1;
            if (count[index, letter] != -1)
                return count[index, letter];
            long ans = 0;
            for (int i = letter + k + 1; i < 26; i++)
                ans += go(index + 1, i);
            if (ans > int.MaxValue)
                ans = int.MaxValue;
            return count[index, letter] = ans;
        }
    }
}