from itertools import groupby

S = list(input())
rle_S = []

for s, array in groupby(S):
    if s == "=":
        rle_S.append((s, len(list(array))))
    else:
        rle_S.extend([(s, 1)] * len(list(array)))

stack = []

for s, length in rle_S:
    stack.append((s, length))
    if len(stack) >= 2:
        pre_s, pre_length = stack[-2]
        if pre_s == s == "=":
            stack.pop()
            stack.pop()
            stack.append((s, length + pre_length))
    
    if len(stack) >= 3:
        pre2_s, pre2_length = stack[-3]
        if pre2_s + pre_s + s == "<=>":
            stack.pop()
            stack.pop()
            stack.pop()

print(sum(length for _, length in stack))