#include<bits/stdc++.h>
// #include<atcoder/all>
using namespace std;
// using namespace atcoder;
using lint = long long;
template<class T>using graph = vector<vector<T>>;
#define endl '\n'
int const INF = 1<<30;
lint const INF64 = 1LL<<62;
lint const mod = 1e9+7;
//long const mod = 998244353;


int main(){
    lint n,x;
    cin >> n >> x;
    lint s[n];
    for(int i=0;i<n;i++)cin >> s[i];
    lint summ = 0;
    for(int i=0;i<n;i++){
        summ += s[i];
    }
    cout << summ - (n-1)*x << endl;
}