def f():
    global ans, S, t, q
    S = 0
    if t:
        ans += len(t)
        t = []
    for l, _ in q:
        ans += len(l)
        q = []

s = input()

t = []
q = []

S = 0
ans = 0
for c in s:
    if c == '<':
        if S:
            q.append((t, S))
        t = ['<']
        S = 1
    elif c == '=':
        t.append('=')
        if S == 1 or S == 2:
            S = 2
        else:
            f()
    else:
        if S == 2:
            if q:
                t, S = q.pop()
            else:
                t, S = [], 0
        else:
            t.append('>')
            f()
f()
print(ans)