stk = [(None, False)]
for s in input():
  if s == '<':
    stk.append((s, True))
  if s == '=':
    if stk[-1][1]:
      stk.append((s, True))
    else:
      stk.append((s, False))
  if s == '>':
    if stk[-1] == ('=', True):
      while stk[-1][0] == '=':
        assert stk.pop() == ('=', True)
      assert stk.pop() == ('<', True)
    else:
      stk.append((s, False))

print(len(stk) - 1)