#include <iostream>
#include <algorithm>
#include <utility>
#include <vector>
#include <stack>
#include <map>
#include <queue>
#include <set>
#include <unordered_set>
#include <unordered_map>
#include <cstring>
#include <cmath>
#include <functional>
#include <cassert>
#include <iomanip>
#include <numeric>
#include <bitset>
#include <sstream>
#include <chrono>
#include <random>
#define ff first
#define ss second
#define PB push_back
#define sz(x) int(x.size())
#define rsz resize
#define fch(xxx, yyy) for (auto xxx : yyy) // abusive notation
#define all(x) (x).begin(),(x).end()
#define eps 1e-9
// more abusive notation (use at your own risk):
// #define int ll
using namespace std;
typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using vi = vector<int>;
using vll = vector<ll>;
// debugging
void __print(int x) {std::cerr << x;}
void __print(ll x) {std::cerr << x;} /* remember to uncomment this when not using THE MACRO */
void __print(unsigned x) {std::cerr << x;}
void __print(ull x) {std::cerr << x;}
void __print(float x) {std::cerr << x;}
void __print(double x) {std::cerr << x;}
void __print(ld x) {std::cerr << x;}
void __print(char x) {std::cerr << '\'' << x << '\'';}
void __print(const char *x) {std::cerr << '\"' << x << '\"';}
void __print(const string& x) {std::cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}
template<typename T, typename V> void __print(const pair<T, V> &x) {std::cerr << '{'; __print(x.ff); std::cerr << ", "; __print(x.ss); std::cerr << '}';}
template<typename T> void __print(const T& x) {int f = 0; std::cerr << '{'; for (auto &i: x) std::cerr << (f++ ? ", " : ""), __print(i); std::cerr << "}";}
void _print() {std::cerr << "]\n";}
template <typename T, typename... V> void _print(T t, V... v) {__print(t); if (sizeof...(v)) std::cerr << ", "; _print(v...);}
void println() {std::cerr << ">--------------------<" << endl;}
#ifndef ONLINE_JUDGE
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
#define debug(x...)
#endif
// templates
template <class T> bool ckmin(T &a, const T &b) {return b<a ? a = b, 1 : 0;}
template <class T> bool ckmax(T &a, const T &b) {return b>a ? a = b, 1 : 0;}
template <class T> using gr = greater<T>;
template <class T> using vc = vector<T>;
template <class T> using p_q = priority_queue<T>;
template <class T> using pqg = priority_queue<T, vc<T>, gr<T>>;
template <class T1, class T2> using pr = pair<T1, T2>;
mt19937_64 rng_ll(chrono::steady_clock::now().time_since_epoch().count());
int rng(int M) {return (int)(rng_ll()%M);} /*returns any random number in [0, M) */
// const variables
constexpr int INF = (int)2e9;
constexpr int MOD = 998244353;
constexpr long double EPS = (ld)1e-10, PI = 3.1415926535;
constexpr ll LL_INF = (ll)3e18;
constexpr int mod = (int)1e9 + 7;
constexpr ll inverse = 500000004LL; // inverse of 2 modulo 1e9 + 7
void setIO(const string& str) {// fast input/output
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
if (str.empty()) return;
freopen((str + ".in").c_str(), "r", stdin);
freopen((str + ".out").c_str(), "w", stdout);
}
//#include "popa.h"
const int MAXN = int(2000) + 5;
int parent[MAXN];
int query(int a, int b, int c, int d);
/*
int S[MAXN];
template<typename T> T gcd(T a, T b) {
a = abs(a), b = abs(b);
while (b) {
T r = a % b;
if (r > (b >> 1)) r = b - r;
a = exchange(b, r);
}
return a;
};
int query(int a, int b, int c, int d) {
int gcd1 = S[a];
for (int i = a; i <= b; ++i) {
gcd1 = gcd(gcd1, S[i]);
}
int gcd2 = S[c];
for (int i = c; i <= d; ++i) {
gcd2 = gcd(gcd2, S[i]);
}
return gcd1 == gcd2;
}
*/
int solve(int N, int* Left, int* Right) {
parent[0] = Left[0] = Right[0] = -1;
for (int i = 1; i < N; ++i) {
int j = i - 1;
while (parent[j] != -1 && query(j, i, i, i)) {
j = parent[j];
}
if (query(j, i, i, i)) {
parent[j] = i;
Left[i] = j;
Right[i] = -1;
parent[i] = -1;
} else {
int r = Right[j];
Right[j] = i;
Left[i] = r;
Right[i] = -1;
parent[i] = j;
parent[r] = i;
}
}
int root = -1;
for (int i = 0; i < N; ++i) {
if (parent[i] == -1) root = i;
}
return root;
}
/*
signed main() { // TIME YOURSELF !!!
setIO("");
int N;
cin >> N;
for (int i = 0; i < N; ++i) {
cin >> S[i];
}
int left[N], right[N];
cout << solve(N, left, right) << '\n';
for (int i = 0; i < N; ++i) {
cout << "i: " << i << '\n';
cout << left[i] << ' ' << right[i] << '\n';
cout << parent[i] << '\n';
}
return 0;
}*/
// TLE -> TRY NOT USING DEFINE INT LONG LONG
// CE -> CHECK LINE 45
// 5000 * 5000 size matrices are kinda big (potential mle)
// Do something, start simpler
