#include "secret.h"
#include <bits/stdc++.h>
#define fi first
#define se second
#define mp make_pair
#define ss(x) (int) x.size()
#define pb push_back
#define ll long long
#define cat(x) cerr << #x << " = " << x << endl
#define FOR(i, n) for(int i = 0; i < n; ++i)
using namespace std;
int n;
int a[1024];
int val[1024][11];
void dc(int l, int r, int lvl) {
if(l >= r) return;
int m = (l + r) / 2;
val[m][lvl] = a[m];
for(int j = m - 1; l <= j; --j)
val[j][lvl] = Secret(a[j], val[j + 1][lvl]);
val[m + 1][lvl] = a[m + 1];
for(int j = m + 2; j <= r; ++j)
val[j][lvl] = Secret(a[j], val[j - 1][lvl]);
dc(l, m, lvl + 1);
dc(m + 1, r, lvl + 1);
}
void Init(int N, int A[]) {
n = N;
for(int i = 0; i < n; ++i)
a[i] = A[i];
dc(0, n - 1, 0);
}
int solve(int x, int y, int l, int r, int lvl = 0) {
int m = (l + r) / 2;
if(x <= m && m + 1 <= y)
return Secret(val[x][lvl], val[y][lvl]);
if(y <= m)
return solve(x, y, l, m, lvl + 1);
return solve(x, y, m + 1, r, lvl + 1);
}
int Query(int l, int r) {
if(l == r) return a[l];
return solve(l, r, 0, n - 1);
}
/*int main() {
int A[] = {1, 4, 7, 2, 5, 8, 3, 6};
Init(8, A);
cout << Query(0, 3) << endl;
cout << Query(1, 7) << endl;
cout << Query(5, 5) << endl;
cout << Query(2, 4) << endl;
return 0;
}
*/
