for t in range(int(input())):
a=int(input())
s=input()
L=[]
for i in range(0,a*8,8):
b=s[i:i+8]
k=0
for i in range(8):
if b[i] == 'I':
k += 2**(7-i)
L.append(k)
print("Case #"+str(t+1),end=": ")
for i in L:
print(chr(i),end="")
print()