#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll z = 0;
int main() {
  ll N, sum;
  cin >> N;
  vector<ll> vec(N);
  for (int i = 0; i < N; i++) {
    cin >> vec[i];
    sum += vec[i];
  }
  cout << sum - N << endl;
}
