#include <bits/stdc++.h>
using namespace std;
using P = pair<int, int>;
int main() {
  int n;
  cin >> n;
  vector<int> a(n);
  for (int i = 0; i < n; i++) cin >> a[i];
  int count = 0;
  for (int i = 0; i < n; i++) count += a[i];
  cout << count - 1 << endl;
}
