#include <bits/stdc++.h>
using namespace std;

using Int = long long;
const char newl = '\n';

template<typename T1,typename T2> inline void chmin(T1 &a,T2 b){if(a>b) a=b;}
template<typename T1,typename T2> inline void chmax(T1 &a,T2 b){if(a<b) a=b;}
template<typename T> void drop(const T &x){cout<<x<<endl;exit(0);}
template<typename T=Int>
vector<T> read(size_t n){
  vector<T> ts(n);
  for(size_t i=0;i<n;i++) cin>>ts[i];
  return ts;
}

//INSERT ABOVE HERE
signed main(){
  cin.tie(0);
  ios::sync_with_stdio(0);

  Int n,t;
  cin>>n>>t;
  auto as=read(n);

  map<Int, Int> dp;
  dp[t]=0;
  for(Int a:as){
    map<Int, Int> nx;
    auto push=[&](Int key,Int val){
      if(!nx.count(key)) nx[key]=val;
      chmax(nx[key],val);
    };
    //cout<<a<<endl;
    for(auto[key,val]:dp){
      //cout<<key<<' '<<val<<endl;
      push(key&a,val+abs((key&a)-key));
      push(key|a,val+abs((key|a)-key));
    }
    swap(dp,nx);
  }

  Int ans=0;
  for(auto[key,val]:dp) chmax(ans,val);
  cout<<ans<<newl;
  return 0;
}