import sys
import math
from itertools import product, permutations, combinations, accumulate
from heapq import heapify, heappush, heappop
from collections import deque, defaultdict, Counter
from bisect import bisect, bisect_left, bisect_right
from copy import copy, deepcopy
#from sortedcontainers import SortedSet, SortedList, SortedDict

sys.setrecursionlimit(10**7)
INF = float('inf')
LINF = 1 << 60
MOD = 10**9+7

def mii():
    return map(int, sys.stdin.readline().split())

S = input()
N = len(S)


st = deque()
cut = 0
cur = 0
now = 0

for i in range(N):
    c = S[i]
    if c == "<":
        st.append((i, "<"))
    elif c == "=":
        st.append((i, "="))
    elif c == ">":
        cnt = 0
        while len(st) > 0 and st[-1][1] == "=":
            cnt += 1
            st.pop()
        if len(st) == 0:
            continue
        
        if cnt == 0:
            st.clear()
            cut += now
            now = 0
            continue
        
        if st[-1][1] == "<":
            now += cnt + 2
            st.pop()
        else:
            st.clear()
            cut += now
            now = 0


cut += now

print(N - cut)