S = input()
X = [0] * 8
s = ["ABCDEF"]
D = dict(zip(*s,range(2,8)))
X[1] += len(S)
for s in S:
    X[D[s]] += 1
ans = []
num = 0
for i in range(6):
    if num < X[i]:
        num = X[i]
        ans = [i]
    elif num == X[i]:
        ans.append(i)
print(*ans)