list = []

for i in range(3):
   list.append(int(input()))

#print(list)

Max = list.index(max(list))
Min = list.index(min(list))

list[Max] = "A"
list[Min] = "C"

for i in range(3):
    if i != Max and i != Min:
        list[i] = "B"
        
for i in range(3):
    print(list[i])