S = input()
sgn = 1
rev = 1
ans = 0
for s in S:
    if s.isdecimal():
        ans += rev * sgn * int(s)
        sgn = 1
    elif s == '-':
        sgn = -1
    elif s == '(':
        rev = sgn
        sgn = 1
    elif s == ')':
        rev = 1
print(ans)