#include <bits/stdc++.h>
using namespace std;
const long long inf = 1e9 + 1e7;
const long long INF = 1e18 + 1e9;
string s;
long long n, x, f, Ans;
signed main() {
  cin >> s;
  n = s.length(), f = 1;
  for (long long i = 0; i < n; i++) {
    if (s[i] < 48) {
      Ans += x * f, x = (s[i] - 48);
      f = (s[i] == '-' ? -1 : 1);
    } else
      x = x * 10 + (s[i] ^ 48);
  }
  printf("%lld\n", Ans + x * f);
  return 0;
}
