#!/usr/bin/env python3

import numpy as np

signs = input().strip()
nums = [0] * (len(signs) // 2)

for i in range(0, len(signs), 2):
    if signs[i] == '+':
        nums[i // 2] = 1
    else:
        nums[i // 2] = -1

opers = 0

while True:
    s = sum(nums)
    if abs(s) == len(nums):
        break

    to_flip = -1 if s > 0 else 1

    start = -1
    end = -1

    for i in range(len(nums)):
        if nums[i] == to_flip:
            end = i
            if start == -1:
                start = i
    
    bottom = nums[:start]
    mid = np.array(nums[start:end + 1]) * -1
    end = [] if end + 1 == len(nums) else nums[end + 1:]

    nums = bottom + mid.tolist() + end
    opers += 1

print(opers)