#include <bits/stdc++.h> #define int long long using namespace std; int n,a[100005],k,sum,mx = -2147483648ll; signed main () { freopen("xor.in","r",stdin); freopen("xor.out","w",stdout); cin >> n >> k; for (int i = 1;i <= n;i++) { cin >> a[i]; sum += a[i]; mx = max(mx,(a[i] ^ k) - a[i]); } cout << (mx + sum) << endl; return 0; }