#include <bits/stdc++.h>

using namespace std;
using ll = long long;

int main(){

    ll N, X, S, T=0;
    cin >> N >> X;
    for (int i=0; i<N; i++){
        cin >> S;
        T += S;
    }

    cout << T-(N-1)*X << endl;

    return 0;
}