#include "bits/stdc++.h"
using namespace std;
#ifndef duc_debug
#include "secret.h"
#endif
const int maxn = 1e3 + 3;
int n, a[maxn];
int pref[maxn][maxn];
void solve(int l, int r) {
int mid = (l + r) / 2;
pref[mid][mid] = a[mid];
pref[mid + 1][mid + 1] = a[mid + 1];
for(int i = mid + 2; i <= r; ++i) {
pref[mid + 1][i] = Secret(pref[mid + 1][i - 1], a[i]);
}
for(int i = mid - 1; i >= l; --i) {
pref[mid][i] = Secret(a[i], pref[mid][i + 1]);
}
if(l < mid) {
solve(l, mid);
}
if(mid + 1 < r) {
solve(mid + 1, r);
}
}
void Init(int _n, int _a[]) {
n = _n;
for(int i = 0; i < n; ++i) {
a[i] = _a[i];
}
solve(0, n - 1);
}
int Query(int l, int r) {
int x = 0, y = n - 1;
while(x < y) {
int mid = (x + y) / 2;
if(l <= mid and mid < r) {
return Secret(pref[mid][l], pref[mid + 1][r]);
}
else if(mid == r) return pref[mid][l];
else if(mid < l) x = mid + 1;
else y = mid;
}
return pref[x][x];
}
