#include <bits/stdc++.h>
using namespace std;
int main() {
  string x;
  int ans = 0, p, ex = 0, fg;
  cin >> p >> x;
  ans = p;
  x += '+';
  for (int i = 0; i < x.length(); i++) {
    if (x[i] == '+' || x[i] == '-') {
      ans += fg * ex;
      ex = 0;
    }
    if (x[i] == '+')
      fg = 1;
    else if (x[i] == '-')
      fg = -1;
    ex = ex * 10 + x[i] - '0';
  }
  printf("%d\n", ans);
}
