# -*- coding: utf-8 -*-

h = [[1 for i in range(2)] for j in range(3)]
a = int(input())
b = int(input())
c = int(input())

h[0][0] = a
h[1][0] = b
h[2][0] = c
h[0][1] = "A"
h[1][1] = "B"
h[2][1] = "C"

h.sort()
h.reverse()

for i in range(3):
    print(h[i][1])