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 == '=':
        if S == 1 or S == 2:
            S = 2
            t.append('=')
        else:
            ans += 1
            S = 0
            if t:
                ans += len(t)
                t = []
            for l, _ in q:
                ans += len(l)
                q = []
    else:
        if S == 2:
            if q:
                t, S = q.pop()
            else:
                t, S = [], 0
        else:
            ans += 1
            S = 0
            if t:
                ans += len(t)
                t = []
            for l, _ in q:
                ans += len(l)
                q = []
ans += len(t)
for l in q:
    ans += len(l)
print(ans)