# Read the three heights
ha = int(input())
hb = int(input())
hc = int(input())

# Create a list of tuples containing height and corresponding letter
people = [
    (ha, 'A'),
    (hb, 'B'),
    (hc, 'C')
]

# Sort the list in descending order based on height
sorted_people = sorted(people, key=lambda x: x[0], reverse=True)

# Output the letters in the sorted order
for person in sorted_people:
    print(person[1])