#include <iostream>
#include <cmath>
#include <string>
#include <vector>
#include <algorithm>
#include <utility>
#include <tuple>
#include <cstdint>
#include <cstdio>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <deque>
#include <unordered_map>
#include <unordered_set>
#include <bitset>
#include <cctype>
#include <climits>

#define rep(i, n) for(int i = 0; i < n; i++)
#define per(i, n) for(int i = n - 1; i >= 0; i--)
using ll = long long;
using ld = long double;
#define vi vector<int>
#define vvi vector<vi>
#define vl vector<ll>
#define pii pair<int, int>
#define pll pair<ll, ll>
#define all(a) (a).begin(), (a).end()
#define mod 1000000007
using namespace std;
int main(){
  int n; ll x;
  cin >> n >> x;
  ll tot = 0;
  rep(i, n){
    int a; cin >> a;
    tot += a;
  }
  x *= n - 1;
  cout << tot - x << "\n";
}