#include<bits/stdc++.h>
using namespace std;
#define int long long
int n, m, half, a[50], b[50], num1[1 << 21], num2[1 << 21], cnt1, cnt2, ans;
map<int, int> mp, mp2;
int dfs2(int x, int s, int p) {
	if(x == n + 1) {
		if(!mp2[p]) {
			num2[++ cnt2] = p;
		}
		if(s > mp2[p]) {
			mp2[p] = s;
		}
		return 0;
	}
	dfs2(x + 1, s, p);
	dfs2(x + 1, s + b[x], p ^ a[x]);
}
int dfs(int x, int s, int p) {
	if(x == half + 1) {
		if(!mp[p]) {
			num1[++ cnt1] = p;
		}
		if(s > mp[p]) {
			mp[p] = s;
		}
		return 0;
	}
	dfs(x + 1, s, p);
	dfs(x + 1, s + b[x], p ^ a[x]);
	return 0;
}
signed main() {
    freopen("outsci.in", "r", stdin);
    freopen("outsci.out", "w", stdout);
    cin >> n >> m;
    half = n / 2;
    for(int i = 1; i <= n; i ++) {
    	cin >> a[i];
	}
	for(int i = 1; i <= n; i ++) {
		cin >> b[i];
	}
	dfs(1, 0, 0);
//	for(int i = 1; i <= cnt; i ++) {
//		cout << c[i] << ' ' << mp[c[i]] << endl;
//	}
	dfs2(half + 1, 0, 0);
	for(int i = 1; i <= cnt1; i ++) {
		for(int j = 1; j <= cnt2; j ++) {
			if((num1[i] ^ num2[j]) <= m) {
				ans = max(ans, mp[num1[i]] + mp2[num2[j]]);
			}
		}
	}
	cout << ans << endl;
    return 0;
}