#include <bits/stdc++.h>
using namespace std;

int main()
{
  int n, x, s = 0;
  cin >> n;
  cin >> x;
  vector<int> a(n);
  for (auto &nx : a)
  {
    cin >> nx;
  }
  for (int i = 0; i < n; i++)
  {
    s += a[i];
  }
  s = s - x;
  cout << s << "\n";
  return 0;
}