#include <bits/stdc++.h>
using namespace std;
const int N = 55;
int main() {
  string s;
  cin >> s;
  int res = 0, x = 0, f = 1;
  for (int i = 0; i < s.size();) {
    char c = s[i];
    if (isdigit(c)) {
      while (isdigit(c)) {
        x = x * 10 + c - '0';
        ++i;
        c = s[i];
      }
      res += f * x;
      if (c == '+')
        f = 1;
      else
        f = -1;
      x = c - '0';
      ++i;
    } else {
      assert(0);
    }
  }
  cout << res << endl;
}
