import sys


def debug(*args):
    print(*args, file=sys.stderr)



s = input()
ans = len(s)

left_list = []
right_list = []
i = 0
mid_flg = False
# add = 0
last_left = None
last_right = None
for i in range(len(s)):
    if s[i] == '<':
        left_list.append(i)
        mid_flg = False
    elif s[i] == '=':
        mid_flg = True
    else:
        if mid_flg and left_list and (not right_list or left_list[-1] > right_list[-1]):
            l = left_list.pop()
            ans -= (i-l+1)
            if last_left is not None and l < last_left:
                ans += last_right-last_left+1
            debug(i, l, ans)
            last_left = l
            last_right = i
            if l > 0 and s[l-1] == '=':
                mid_flg = True
            else:
                mid_flg = False
        else:
            right_list.append(i)
            mid_flg = False

print(ans)