#include <bits/stdc++.h>
#include<iostream>
#include<map>
#include<vector>
#include <algorithm>
#include<math.h>
#include <iomanip>
#include<set>
#include <numeric>
#include<string>
using namespace std;


int main()
{
    int n, x, sum1 = 0;
    cin >> n >> x;
    for (int i = 0; i < n; i++){
        int t;
        cin >> t;
        sum1 += t;
    }
    cout << sum1 - x*(n-1) << endl;
}