/*
Telebe of Adicto && Mamedov yani AzeTurk810
I see humans but no humanity
*/
#include "sequence.h"
#include <algorithm>
#include <cassert>
#include <iostream>
#include <map>
#include <set>
#include <utility>
#include <vector>
// mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
using ll = long long;
using namespace std;
#define ln '\n'
#define INFi 1e9
#define INFll 1e18
#ifdef ONPC
#include <algo.hpp>
#else
#define dbg(...)
#define dbg_out(...)
#endif
int _n, ans;
vector<int> A;
map<int, vector<int>> ind;
inline void systemd() {
ans = 1;
for (size_t i = 0; i < _n; i++) {
ind[A[i]].push_back(i);
}
}
int W(int l, int r, int x) {
auto itl = lower_bound(ind[x].begin(), ind[x].end(), l);
auto itr = upper_bound(ind[x].begin(), ind[x].end(), r);
itr--;
return itr - itl + 1;
}
int W(int l, int r, set<int> st) {
int res = 0;
for (int x : st) {
dbg(make_pair(l, r));
dbg(x);
res = max(res, W(l, r, x));
dbg(res);
}
return res;
}
char solve() {
systemd();
for (size_t i = 0; i < _n; i++) {
multiset<int> mst;
mst.insert(A[i]);
auto it1 = mst.begin(), it2 = mst.begin();
for (size_t j = i + 1; j < _n; j++) {
mst.insert(A[j]);
set<int> st;
dbg(mst);
dbg(*it1);
dbg(*it2);
dbg(*(++it1));
it1--;
dbg(i);
dbg(j);
if (A[j] >= *it2) {
if (it1 != it2)
it1++;
else
it2++;
goto nxt;
}
if (A[j] >= *it1) {
if (it1 != it2) {
it1++;
it2--;
assert(it1 == it2);
} else {
it1++;
}
goto nxt;
}
if (it1 != it2) {
it2--;
} else {
it1--;
}
nxt:
dbg(*it1);
dbg(*it2);
assert(*it1 <= *it2);
if (mst.size() & 1) {
assert(it1 == it2);
}
st.insert(*it1);
st.insert(*it2);
ans = max(ans, W(i, j, st));
}
}
return 0;
}
int sequence(int N, std::vector<int> _a) {
_n = N;
A = _a;
assert(!solve());
return ans;
}
// Attack on titan<3
// Just Imaginary
/*
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢀⣀⣀⠀⠀⠀⢀⣴⣾⠀⠀⠀⡀⢀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢸⣿⣿⣿⣦⣾⣿⣿⣿⣿⣿⡆⠁⠀⢀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠹⣿⣿⣿⣿⣿⣿⣿⣿⡿⠁⠀⡠⠂⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣀⠠⠔⠚⣿⣿⣿⣿⣿⣦⡄⠀⠁⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⢀⠠⠐⢂⠉⡀⣀⣤⣄⢻⣿⣿⡟⢈⡹⣿⡀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⡀⠄⠂⠈⠀⣶⣤⣾⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⠘⣷⡀⠀⡀⠐⠂⠐⢄
⠀⠀⠀⠀⠀⠀⠀⣿⣿⠟⠿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣧⣀⣾⣷⠯⠀⠤⠤⠄⠈
⠀⠀⠀⠀⠀⠀⣼⣿⡟⠀⠀⣹⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣷⣄⡀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⣰⣿⠋⠀⠀⢠⣾⣿⣿⣿⣿⣿⣭⠟⢻⣿⣿⣿⣿⡿⠁⠀⠀⠀⠀
⠀⠀⠀⣀⣶⡟⠁⠀⢾⣶⣿⠟⠉⠈⢻⣿⣿⣿⣦⣜⠀⠛⠛⠿⠁⠀⠀⠀⠀⠀
⠚⠻⠿⠿⡿⠁⠀⢠⣿⣿⠁⠀⣠⠖⠋⠉⠻⣿⣿⣿⣶⡀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⣰⣿⡿⠃⠠⠊⠁⠀⠀⠀⠀⠈⢿⣿⣿⠟⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⢀⣴⡿⠋⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠘⠁⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⣠⣾⠏⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⢀⣴⠾⠟⠛⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
7
1 2 3 1 2 1 3
*/
