data = input().strip()
calc_flag = [1]
ans = [0]
for c in data:
    if(c == "("):
        ans.append(0)
        calc_flag.append(1)
    elif(c == ")"):
        tmp = ans[-1]
        ans.pop()
        calc_flag.pop()
        ans[-1] += tmp*calc_flag[-1]
    elif(c == "+"):
        calc_flag[-1] = 1
    elif(c == "-"):
        calc_flag[-1] = -1
    else:
        ans[-1] += calc_flag[-1]*int(c)
print(ans[0])