def findGray(array):
awnsers = ["*", "A", "B", "C", "D", "E"]
found = 0
index = 0
for i,num in enumerate(array):
if num < 128:
found += 1
index = i+1
if found > 1:
return "*"
else:
return awnsers[index]
n = 1;
while n != 0:
n = int(input())
for i in range(0,n):
numbers_array = [int(num) for num in input().split()]
print(findGray(numbers_array))