import sys
from collections import deque, Counter
input = lambda: sys.stdin.readline().rstrip()
ii = lambda: int(input())
mi = lambda: map(int, input().split())
li = lambda: list(mi())
inf = 2 ** 63 - 1
mod = 998244353
import string
S = string.ascii_uppercase
def solve(test):
    n = ii() - 1

    ng = 10 ** 9

    ok = 0

    while abs(ok - ng) > 1:
        mid = (ok + ng) // 2
        if 13 * mid * (mid + 1) <= n:
            ok = mid
        else:
            ng = mid
    turn = ok + 1

    n -= 13 * ok * (ok + 1)

    print('Case #'+str(test) + ':', S[(n // turn % 26)])





for test in range(1, ii() + 1):
    solve(test)