T=int(input())
s="ABCDEFGHIJKLMNOPQRSTUVWXYZ"
for i in range(T):
    a=int(input())
    if (a<=26):
        print("Case #%d: %s"%((i+1),s[a-1]))
    else:
        print("Case #%d: %s"%((i+1),s[(a%26)//(a//26)+1]))