#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  long long int f = 1, t = 0, ans = 0;
  cin >> s;
  for (long long int i = 0; i <= s.length(); i++) {
    if (s[i] < '0') {
      ans += f * t;
      s[i] == '+' ? f = 1 : f = -1;
      t = 0;
    }
    t = t * 10 + s[i] - '0';
  }
  cout << ans << endl;
}
