#include "secret.h"
#include <bits/stdc++.h>
#define pii pair<int, int>
using namespace std;
map<pii, int> D;
int N;
void DnC1(int L, int R) {
if (L >= R) return;
int mid = (L + R) >> 1;
for (int i = mid - 1; i >= L; --i) D[{i, mid}] = Secret(i, mid);
for (int i = mid + 2; i <= R; ++i) D[{mid, i}] = Secret(mid, i);
DnC1(L, mid);
DnC1(mid + 1, R);
}
void Init(int _N, int A[]) {
N = _N;
DnC1(0, N - 1);
for (int i = 0; i < N; ++i) D[{i, i}] = A[i];
}
int DnC2(int L, int R, int s, int e) {
if (L >= R) return -1;
int mid = (L + R) >> 1;
if (s <= mid && mid < e) {
int a = D[{s, mid}], b = D[{mid + 1, e}];
return Secret(a, b);
}
if (e <= mid) return DnC2(L, mid, s, e);
else return DnC2(mid + 1, R, s, e);
}
int Query(int L, int R) {
return DnC2(0, N - 1, L, R);
}
