#include "secret.h"
#include <bits/stdc++.h>
using namespace std;
#define rep(i, a, b) for (int i = (a); i < (b); ++i)
#define per(i, a, b) for (int i = (b - 1); i >= (a); --i)
#define trav(a, x) for (auto &a : x)
#define all(x) x.begin(), x.end()
#define sz(x) x.size()
#define pb push_back
#define debug(x) cout << #x << " = " << x << endl
#define umap unordered_map
#define uset unordered_set
typedef pair<int, int> ii;
typedef pair<int, ii> iii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<vi> vvi;
typedef long long ll;
typedef pair<ll, ll> pll;
typedef vector<ll> vll;
typedef vector<pll> vpll;
const int INF = 1'000'000'007;
int precomp[1001][1001], nums[1001];
int n;
void dnc(int lo, int hi) {
if (lo >= hi) return;
int mid = (lo + hi) / 2;
precomp[mid][mid] = nums[mid];
precomp[mid + 1][mid + 1] = nums[mid + 1];
per(i, lo, mid) precomp[mid][i] = Secret(nums[i], precomp[mid][i + 1]);
rep(i, mid + 2, hi + 1) precomp[mid + 1][i] = Secret(nums[i], precomp[mid + 1][i - 1]);
dnc(lo, mid);
dnc(mid + 1, hi);
}
void Init(int N, int A[]) {
memset(precomp, -1, sizeof(precomp));
rep(i, 0, N) nums[i] = A[i];
dnc(0, N - 1);
n = N;
}
int Query(int L, int R) {
if (L == R) return nums[L];
int lo = 0, hi = n - 1;
while (1) {
int mid = (lo + hi) / 2;
if (L <= mid && mid < R) return Secret(precomp[mid][L], precomp[mid + 1][R]);
if (R == mid) return precomp[mid][L];
if (mid < L)
lo = mid + 1;
else
hi = mid;
}
return 0;
}
