#include <bits/stdc++.h>
#define ll long long
#define all(lpv) lpv.begin(), lpv.end()
#define fi first
#define se second
#define pot(x, y) lower_bound(x.begin(), x.end(), y) - x.begin()
using namespace std;
#ifndef lpv
#include "sequence.h"
#endif // lpv
const int N = 5e5 + 5;
const int oo = 1e9;
int n, a[N], bit[N], s[N], t[N], c[N], id[N], ans;
vector<int> col[N];
struct node {
int lz, mx, mi;
} st[N << 2];
// 0 small - big
// 1 big - small
void build(int i,int l,int r) {
if(l == r) {
st[i].lz = 0;
st[i].mx = st[i].mi = l;
return;
}
int mid = (l + r) / 2;
build(i << 1, l, mid);
build(i << 1|1, mid + 1, r);
st[i].lz = 0;
st[i].mx = max(st[i << 1].mx, st[i << 1|1].mx);
st[i].mi = min(st[i << 1].mi, st[i << 1|1].mi);
}
void pro(int i,int x) {
st[i].lz += x;
st[i].mx += 2 * x;
st[i].mi += 2 * x;
}
void dolz(int i) {
if(!st[i].lz) return;
int x = st[i].lz; st[i].lz = 0;
pro(2 * i, x);
pro(2 * i + 1, x);
}
void add(int i,int l,int r,int u,int v,int x) {
if(l > r || u > v || r < u || v < l) return;
if(u <= l && r <= v) {
pro(i, x);
return ;
}
dolz(i);
int mid = (l + r) / 2;
add(i << 1, l, mid, u, v, x);
add(i << 1|1, mid + 1, r, u, v, x);
st[i].lz = 0;
st[i].mx = max(st[i << 1].mx, st[i << 1|1].mx);
st[i].mi = min(st[i << 1].mi, st[i << 1|1].mi);
}
int get_max(int i,int l,int r,int u,int v) {
if(l > r || u > v || r < u || v < l) return -oo;
if(u <= l && r <= v) return st[i].mx;
dolz(i);
int mid = (l + r) / 2;
return max(get_max(i << 1, l, mid, u, v), get_max(i << 1|1, mid + 1, r, u, v));
}
int get_min(int i,int l,int r,int u,int v) {
if(l > r || u > v || r < u || v < l) return oo;
if(u <= l && r <= v) return st[i].mi;
dolz(i);
int mid = (l + r) / 2;
return min(get_min(i << 1, l, mid, u, v), get_min(i << 1|1, mid + 1, r, u, v));
}
int sequence(int _n, vector<int> A) {
n = _n;
ans = 1;
for(int i = 1; i <= n; i ++) {
a[i] = A[i - 1];
col[a[i]].push_back(i);
}
build(1, 0, n);
for(int k = 1; k <= n; k ++) if(!col[k].empty()) {
vector<int> rrh;
int sz = col[k].size();
vector<int> mxr, mir, mxl, mil;
for(int i = 0; i < sz; i ++) {
int x = col[k][i];
mxr.push_back(get_max(1, 0, n, x, n));
mil.push_back(get_min(1, 0, n, 0, x - 1));
}
for(int i = 0; i < sz; i ++) {
int x = col[k][i];
add(1, 0, n, x, n, -1);
}
for(int i = 0; i < sz; i ++) {
int x = col[k][i];
mir.push_back(get_min(1, 0, n, x, n));
mxl.push_back(get_max(1, 0, n, 0, x - 1));
}
for(int i = sz - 1; i >= 0; i --) {
while(i + ans < sz && mxr[i + ans] >= mil[i] && mir[i + ans] <= mxl[i]) ++ans;
}
}
return ans;
}
/*
7
1 2 3 1 2 1 3
3
9
1 1 2 3 4 3 2 1 1
2
14
2 6 2 5 3 4 2 1 4 3 5 6 3 2
3
*/
#ifdef lpv
signed main() {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define task "v"
if(fopen(task ".inp","r")) {
freopen(task ".inp","r",stdin);
freopen(task ".out","w",stdout);
}
int _n; cin >> _n;
vector<int> A;
for(int i = 1; i <= _n; i ++) {
int x; cin >> x;
A.push_back(x);
}
int result = sequence(_n, A);
cout << result;
}
#endif // lpv
