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

const int maxn = 101;

int T, n, m, q;
ll K;
int cnt = 0;

struct LinearBasis{
    ll a[maxn + 10];
    int b[maxn];
    
    int insert(ll t){
        for(int j = 62 ; j >= 0 ; --j){
            if(!t) return 0;
            if(t & (1ll << j)){
                if(a[j]){
                    t = t ^ a[j];
                } else{
                    for(int k = 0 ; k < j ; ++k){
                        if(t & (1ll << k)) t = t ^ a[k];
                    }
                    for(int k = j + 1 ; k <= 62 ; ++k){
                        if(a[k] & (1ll << j)) a[k] = a[k] ^ t;
                    }
                    a[j] = t;
                    return 1;
                }
            }
        }
        return 0;
    }
}A;

bool check(ll k){
        ll ans = 0;
        for(int i = 0 ; i <= 62 ; ++i){
            if((k >> i) & 1){
                ans ^= A.a[i];
            }
        }
        return ans > K;
//    }
}

ll read(){ ll s = 0, f = 1; char ch = getchar(); while(ch < '0' || ch > '9'){ if(ch == '-') f = -1; ch = getchar(); } while(ch >= '0' && ch <= '9'){ s = s * 10 + ch - '0'; ch = getchar(); } return s * f; }

int main(){
//    freopen("data.in", "r", stdin);
//    freopen("my.out", "w", stdout);
        n = read(), K = read();
        ll x; 
        for(int i = 1 ; i <= n ; ++i){
            x = read();
            cnt += A.insert(x);
        }
        
        for (int i = 0, j = 0; i <= 62; ++i)
        if (A.a[i])
            A.a[j++] = A.a[i];
        
        ll l = 0, r = (1 << cnt) - 1; 
        while(l < r){
            ll mid = (l + r + 1) >> 1;
            if(check(mid)){
                r = mid - 1;
            } else{
                l = mid;
            }
        }
//        printf("%lld\n", r);
        
        cout << (1 << cnt) - l - 1;

    return 0;
}