#include<iostream>
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<algorithm>
#include<vector>
#include<math.h>
#include<iomanip>
#include<stack>
#include<queue>
#include<set>
#include<map>

using namespace std;
using ll = long long;
using ull = unsigned long long;
using ld = long double;

//const ll mod = 1000000007;
const ll mod = 998244353;
const ld pi = 3.14159265358979;
const ll inf = 1e18;

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	//cout << fixed << setprecision(15);
	int n , x;
	cin >> n >> x;
	ll sum = 0;
	vector<int> s(n);
	for(int i = 0; i < n; i++){
		cin >> s[i];
		sum += s[i];
	}
	ll t = sum - (ll)x * (n - 1);
	for(int i = 0; i < n; i++){
		if(t * 2 == s[i]){
			cout << t << endl;
			exit(0);
		}
	}

	return 0;
}