#include"testlib.h"
#include<iostream>
#include<vector>
#include<string>
#include<map>
#include<set>
#include<queue>
#include<algorithm>
#include<cmath>
#include<iomanip>
#include<random>
#include<stdio.h>
using namespace std;

typedef long long ll;
const long long MIN_N = 1;
const long long MAX_N = 200000;
const long long MIN_X = 0;
const long long MAX_X = 1000000000;
const long long MIN_S = 1;
const long long MAX_S = 1000000000;

void validate(){
  long long N = inf.readLong(MIN_N,MAX_N);
  inf.readSpace();
  long long X = inf.readLong(MIN_X,MAX_X);
  inf.readEoln();

  long long Sum = 0;
  long long S;
  set<ll> T;
  for (long long i=0;i<N;i++){
    S = inf.readLong(MIN_S,MAX_S);
    T.insert(S);
    Sum += S;
    if (i!=N-1){
      inf.readSpace();
    }
    else{
      inf.readEoln();
    }
  }

  Sum -= (N-1) * X;
  if (T.find(2*Sum)==T.end()){
    for (int i=0;i<10;i++){
      inf.readEoln();
    }
  }
  else{
    inf.readEof();
  }
  cout<<Sum<<endl;
}

int main(int argc, char* argv[]){
  registerValidation(argc,argv);
  validate();
}