#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
  #include "settings/debug.cpp"
#else
  #define Debug(...) void(0)
#endif
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  ll n, x;
  cin >> n >> x;
  vector<ll> s(n);
  rep(i, n) cin >> s[i];
  cout << accumulate(s.begin(), s.end(), 0LL) - (n - 1) * x << endl;
  return 0;
}