#include <iostream>
#include <stack>
using namespace std;
int main(){
    string s;cin>>s;
    stack<int> nya;
    int nw = 1;
    bool num = false;
    char ke = 'e';
    for(int i = 0; s.size() > i; i++){
        if(!num && s[i] == '+')continue;
        else if(!num && s[i] == '-')nw *= -1;
        else if(!num)nw *= s[i]-'0',num = true;
        else if('0' <= s[i] && s[i] <= '9')nw = nw*10+s[i]-'0';
        else{
            nya.push(nw);
            num = false;
            nw = 1;
            if(s[i] == '+')ke = '-';
            else ke = '+';
        }
    }
    cout << nya.top()+(ke=='+'?nw:-nw) << endl;
}