def get_letter(n):
    n -= 1
    i = 1
    while n >= i * 26:
        n -= i * 26
        i += 1
    return chr(ord('A') + n // i)

t = int(input())
for i in range(t):
    n = int(input())
    print("Case #{}: {}".format(i + 1, get_letter(n)))