import os
import io
import sys
from math import *
from collections import defaultdict as dd
from collections import *
import time
import itertools as it
import string
from functools import lru_cache, reduce
# sourcery skip: de-morgan
adj = [(-1, 0), (0, 1), (1, 0), (0, -1)]
adj4 = adj
directions = {
    "N": (-1, 0),
    "S": (1, 0),
    "E": (0, 1),
    "W": (0, -1),
    "U": (-1, 0),
    "D": (1, 0),
    "L": (0, -1),
    "R": (0, 1),
    "^": (-1, 0),
    "V": (1, 0),
    "v": (1, 0),
    "<": (0, -1),
    ">": (0, 1),
}
complement = {
    "N": "S",
    "S": "N",
    "E": "W",
    "W": "E",
    "U": "D",
    "D": "U",
    "L": "R",
    "R": "L",
}
complements = complement
adj8 = [(i, j) for i in range(-1, 2)
        for j in range(-1, 2)
        if not (i == 0 and j == 0)]
enu = enumerate
def prod2(x):
    res = 1
    for i in x:
        res *= i
    return res

def print_board(board, sep=''):
    # print(f"{x_pos=} {y_pos=}")
    lo_y = min(board.keys(), key=lambda x: x[0])[0]
    hi_y = max(board.keys(), key=lambda x: x[0])[0]
    lo_x = min(board.keys(), key=lambda x: x[1])[1]
    hi_x = max(board.keys(), key=lambda x: x[1])[1]
    for y in range(lo_y, hi_y + 1):
        for x in range(lo_x, hi_x + 1):
            print(board[y, x], end=sep)
        print()

input2 = io.BytesIO(os.read(0, os.fstat(0).st_size)).readline
def debug(*args, **kwargs):
    print(*args, "]]", **kwargs, file=sys.stderr)

def manhat(p1, p2):
    '''returns manhattan distance between two points'''
    return sum(abs(a-b) for a, b in zip(p1, p2))

def printe(x, sort=False):
    it = x
    if sort:
        it = sorted(it)
    if isinstance(x, dict):
        it = sorted(x.keys())
    for i in it:
        if isinstance(x, dict):
            debug(i, x[i])
        else:
            debug(i)
def num():
    return(int(input2()))
def nums():
    return(list(map(int,input2().split())))
def words():
    return input().split()
def input():
    return(input2().strip().decode("utf-8"))
def t_sorted(x):
    return tuple(sorted(x))
def solve():# sourcery skip: for-index-underscore, remove-redundant-pass
    n = num()
    letters = string.ascii_uppercase
    to_remove = 26
    times = 1
    while n - to_remove > 0:
        n -= to_remove
        to_remove += 26
        times += 1
    debug(n)
    return letters[(n-1)//times]
    
    pass
def floats():
    return(list(map(float,input2().split())))
def str_list(lis, sep=' '):
    return sep.join(list(map(str, lis)))

def main():
    # debug("test")
    cases = num()
    for t in range(1, cases+1):
        sys.stdout.write(f"Case #{t}: ")
        sys.stdout.write(f"{solve()}\n")

main()