if __name__ == '__main__':
    s = input()
    c1 = 0
    c2 = 0
    for idx in range(1,len(s)):
        if s[idx] == s[idx-1]:
            if s[idx] == '+':
                c1 += 1
            else:
                c2 += 1
    print(abs(c1-c2) + max(c1 - abs(c1-c2), c2 - abs(c1 -c2) ))