#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < int(n); i++)
#define rrep(i,n) for(int i = int(n)-1; i >= 0; i--)
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define pb push_back
using namespace std;
using ll = long long;
using Pi = pair<int,int>;
using Pll = pair<ll,ll>;
template<class T> bool chmax(T &a, const T &b) {if(a < b) {a = b; return true;} return false;}
template<class T> bool chmin(T &a, const T &b) {if(b < a) {a = b; return true;} return false;}
int dx[] = {1, 0,-1, 0, 1, 1,-1,-1};
int dy[] = {0, 1, 0,-1, 1,-1, 1,-1};
ll mod = 998244353;
ll MOD = 1000000007;
int inf = 1001001001;
ll INF = 1001001001001001001;
int main() {
    int N,X;
    cin >> N >> X;
    vector<int>S(N);
    ll sum = 0;
    rep(i,N) {
        cin >> S[i];
        sum += S[i];
    }
    cout << (sum-X*(N-1)) << endl;
}