#include <bits/stdc++.h>
using namespace std;
int ans;
char s[1001];
int main() {
  cin >> ans >> s;
  for (int i = 0; s[i];) {
    int j = i + 1, res = s[i] - '0';
    while (isdigit(s[j])) {
      res = res * 10 + s[j] - '0';
      j++;
    }
    if (s[i] == '+')
      ans += res;
    else
      ans -= res;
    i = j;
  }
  cout << ans << endl;
}
