#include <bits/stdc++.h>
using namespace std;
vector<vector<int>> matrix_multiplication(vector<vector<int>> A, vector<vector<int>> B){
  int N = A.size();
  vector<vector<int>> ans(N, vector<int>(N, 0));
  for (int i = 0; i < N; i++){
    for (int j = 0; j < N; j++){
      for (int k = 0; k < N; k++){
        ans[i][k] ^= A[i][j] * B[j][k];
      }
    }
  }
  return ans;
}
vector<vector<int>> matrix_exponentiation(vector<vector<int>> A, long long n){
  int N = A.size();
  vector<vector<int>> ans(N, vector<int>(N, 0));
  for (int i = 0; i < N; i++){
    ans[i][i] = 1;
  }
  while (n > 0){
    if (n % 2 == 1){
      ans = matrix_multiplication(ans, A);
    }
    A = matrix_multiplication(A, A);
    n /= 2;
  }
  return ans;
}
int main(){
  int N;
  long long K;
  cin >> N >> K;
  K--;
  vector<long long> A(N);
  for (int i = 0; i < N; i++){
    cin >> A[i];
  }
  if (K < N){
    cout << A[K] << endl;
  } else {
    vector<vector<int>> B(N, vector<int>(N, 0));
    for (int i = 0; i < N; i++){
      B[i][0] = 1;
    }
    for (int i = 0; i < N - 1; i++){
      B[i][i + 1] = 1;
    }
    B = matrix_exponentiation(B, K - N + 1);
    long long ans = 0;
    for (int i = 0; i < N; i++){
      if (B[i][0] == 1){
        ans ^= A[N - 1 - i];
      }
    }
    cout << ans << endl;
  }
}