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

int main() {
    int N;
    long long K;
    cin >> N >> K;
    long long sum = 0;
    vector<long long>A(N);
    for(int i = 0; i < N; i++) {
        cin >> A[i];
        sum ^= A[i];
    }
    K -= N;
    if(K%(N+1) == 1) {
        cout << sum << endl;
    }
    else {
        if(K%(N+1) == 0) {
            cout << A[N-1] << endl;
        }
        else {
            cout << A[K%(N+1)-2] << endl;
        }
    }
}