#include<iostream>
#include<cmath>
#include<stack>
#include<string>

using namespace std;

int is_it_num(char a){
    if ((a - '0') <= 9 && (a - '0') >= 0) return 1;
    else return 0;
}

int num(char a){
    return a - '0';
}

int do_it(char c, int a, int b){
    if(c == '+') return a + b;
    else if(c == '-') return a - b;
}

int main(){
    string s;
    cin >> s;

    stack<int> numbers;
    stack<char> operators;

    if(is_it_num(s[0])) numbers.push(num(s[0]));

    for(int i = 1; i < s.size(); ++i){ //если мы встретили цифру
        if (is_it_num(s[i]))
            if (is_it_num(s[i - 1])){
                int top = numbers.top();
                numbers.pop();
                numbers.push(top * 10 + num(s[i]));
            }
            else{
                numbers.push(num(s[i]));
            }
        else{ // если мы встретили оператор
            while ( !(operators.empty()) && (operators.top() != '(')){
                int top_1 = numbers.top();
                numbers.pop();
                int top_2 = numbers.top();
                numbers.pop();
                numbers.push(do_it(operators.top(), top_2, top_1));
                operators.pop();
                cout << "top = " << numbers.top() << endl;
            }


            if(s[i] == ')') {
                operators.pop();
                if (numbers.top() < 0){
                    if(operators.top() == '-'){
                        operators.pop();
                        operators.push('+');
                        int a = numbers.top();
                        numbers.pop();
                        numbers.push((-1)*a);
                    }
                    else{
                        int a = numbers.top();
                        numbers.pop();
                        numbers.push((-1)*a);
                        operators.pop();
                        operators.push('-');
                    }
                }
            }
            else {
                operators.push(s[i]);
            }
        }
    }

    while (!(operators.empty())){
        int top_1 = numbers.top();
        numbers.pop();
        int top_2 = numbers.top();
        numbers.pop();
        numbers.push(do_it(operators.top(), top_2, top_1));
        operators.pop();
    }

    cout << numbers.top() << endl;

    return 0;
}