#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <utility>
#include <map>
using namespace std;
typedef long long ll;
#define rep(i, n) for (int i=0;i < (int)(n);i++)

int main(){
  ll n,x;
  cin >> n >> x;
  ll sum = 0;
  for (int i = 0; i < n;i++){
    ll tmp;
    cin >> tmp;
    sum += tmp;
  }
  cout << x-x*n+sum << endl;
}