#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef unsigned long long ull;
 
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ll myRand(ll B) {
    return (ull)rng() % B;
}

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    ll n; cin >> n;
    ll x; cin >> x;
    vector<ll> s(n);
    ll sum=0;
    for(int i=0;i<n;i++){
        cin >> s[i];
        sum+=s[i];
    }
    cout << x-(x*n-sum) << endl;
}