#include <bits/stdc++.h>

using namespace std;

#define int long long
#define all(v) (v).begin(), (v).end()
#define resz(v, ...) (v).clear(), (v).resize(__VA_ARGS__)
#define reps(i, m, n) for(int i = (int)(m); i < (int)(n); i++)
#define rep(i, n) reps(i, 0, n)

template<class T1, class T2> void chmin(T1 &a, T2 b){if(a>b)a=b;}
template<class T1, class T2> void chmax(T1 &a, T2 b){if(a<b)a=b;}

using Pi = pair<int, int>;
using Tapris = tuple<int, int, int>;
using vint = vector<int>;

const int inf = 1LL << 55;
const int mod = 1e9 + 7;

int lcm(int a, int b) {
  return a / __gcd(a, b) * b;
}

signed main() {
  cin.tie(0);
  ios_base::sync_with_stdio(0);
  cout << fixed << setprecision(12);

  int n;
  cin >> n;
  vint a(n);
  int LCM = 1;
  rep(i, n) {
    cin >> a[i];
    LCM = lcm(LCM, a[i]);
  }
  //cout << LCM << endl;
  int sum = 0;
  rep(i, n) sum += (LCM-1)%a[i];
  cout << sum << endl;


  return 0;
}
