#include<bits/stdc++.h> using namespace std; int n,k; long long a[200005]; int ans = -2e9; int sum=0; int main(){ // freopen("xor.in","r",stdin); // freopen("xor.out","w",stdout); scanf("%d%d",&n,&k); for(int i = 1;i<=n;i++){ cin>>a[i]; sum+=a[i]; } for(int i = 1;i<=n;i++){ int tmp = a[i]^k-a[i]; ans=max(ans,sum+tmp); } cout<<ans<<endl; }