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

long long n, x;
vector<long long> s;

long long solve();

int main() {
  cin >> n >> x;
  s.resize(n);
  for (auto &p : s) cin >> p;
  cout << solve() << endl;
  return 0;
}

long long solve() {
  long long sum = 0;
  for (auto p : s) sum += p;
  sum -= (n - 1) * x;
  return sum;
}