#include <cstdio>
#include <algorithm>
#include <functional>
using namespace std;
struct decision {
    int apos, bpos;
    long long value;
};
bool operator < (decision a, decision b) {
    return a.value < b.value;
}
int n, m;
long long a[100010], b[100010];
decision dp[1000010];
decision nexta(decision now) {
    decision res;
    res.apos = now.apos + 1;
    res.bpos = now.bpos;
    if (res.apos <= n) {
        res.value = now.value + a[res.apos];
    } else {
        res.value = -1e18;
    }
    return res;
}
decision nextb(decision now) {
    decision res;
    res.apos = now.apos;
    res.bpos = now.bpos + 1;
    if (res.bpos <= n) {
        res.value = now.value + b[res.bpos];
    } else {
        res.value = -1e18;
    }
    return res;
}
int main() {
    scanf("%d%d", &n, &m);
    for (int i = 1; i <= n; i++) {
        scanf("%lld", &a[i]);
    }
    for (int i = 1; i <= n; i++) {
        scanf("%lld", &b[i]);
        b[i] += a[i];
    }
    sort(a + 1, a + n + 1, greater<int>());
    sort(b + 1, b + n + 1, greater<int>());
    long long ans = 0;
    for (int i = 1; i <= m; i++) {
        if (i > 3 * n) {
            dp[i] = dp[3 * n];
        } else if (i >= 2) {
            dp[i] = max(nexta(dp[i - 1]), nextb(dp[i - 2]));
        } else {
            dp[i] = nexta(dp[i - 1]);
        }
        // printf("%d : %d %d %lld\n", i, dp[i].apos, dp[i].bpos, dp[i].value);
        ans ^= dp[i].value;
    }
    printf("%lld\n", ans);
    return 0;
}