# import pypyjit
# pypyjit.set_param('max_unroll_recursion=-1')
from collections import defaultdict as dd
S = input
R = range
P = print
def I(): return int(S())
def M(): return map(int, S().split())
def L(): return list(M())
def O(): return list(map(int, open(0).read().split()))
def yn(b): print("Yes" if b else "No")
biga = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
smaa = "abcdefghijklmnopqrstuvwxyz"
ctoi = lambda c: ord(c) - ord('a')
itoc = lambda i: chr(ord('a') + i)
inf = 10 ** 18
mod = 998244353
def acc(a):
	b = [0]
	for i in a:
		b.append(b[-1] + i)
	return b

s=S()
par=[]
u=[]
for i in s:
	c=True
	if i=='>':
		if len(par)>0 and par[-1]=='<'and len(u)>0 and u[-1]=='=':
			while u[-1]=='=':u.pop()
			u.pop()
			par.pop()
			c=False
		else:
			u.append(i)
	else:
		u.append(i)
	if i in"<>" and c:
		par.append(i)
P(len(u))