def f(L, R):
    val = 0
    pm = 1
    flag = 0
    i = L
    while i != R:
        if S[i] == "+":
            pm = 1
        elif S[i] == "-":
            pm = -1
        elif S[i] == "(":
            val += pm * f(i + 1, D[i])
            i = D[i] + 1
            continue
        else:
            val += pm * int(S[i])
        i += 1
    return val
 

S = list(input())
N = len(S)
stack = []
D = dict()
for i in range(N):
    if S[i] == ")":
        while stack[-1][0] != "(":
            stack.pop()
        _, ind = stack.pop()
        D[ind] = i
    else:
        stack.append((S[i], i))

print(f(0, N))