#include <bits/stdc++.h>
#define rep(i, ss, ee) for (int i = ss; i < ee; ++i)
using namespace std;

int solve() {
  int N, A, x;
  int ans = 0;
  cin >> N;
  rep(i, 0, N) {
    cin >> x;
    ans += x;
  }
  cin >> A;
  return ans - A;
}

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << solve() << endl;
  getchar();
}