import sys; input = sys.stdin.buffer.readline
sys.setrecursionlimit(10**7)
from collections import defaultdict
con = 10 ** 9 + 7; INF = float("inf")

def getlist():
	return list(map(int, input().split()))

#処理内容
def main():
	Ha, Wa = getlist()
	Hb, Wb = getlist()
	Hc, Wc = getlist()
	L = [[Ha, -Wa, "A"], [Hb, -Wb, "B"], [Hc, -Wc, "C"]]
	L.sort()
	for i in range(2, -1, -1):
		print(L[i][2])

if __name__ == '__main__':
	main()