#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
using ld = long double;

int N, X, S[202020];
ll sum;

int main() {
  cin >> N >> X;
  for (int i = 1; i <= N; i++) {
    cin >> S[i];
    sum += S[i];
  }
  cout << sum - X * (N - 1) << endl;
  return 0;
}