Shared code

/* 777 */
#include "bits/stdc++.h"
using namespace std;
 
#define int long long 
#define endl '\n'
#define all(x) x.begin(),x.end()
#define sortf(x) sort(all(x))
#define sortfn(x,fn) sort(all(x),fn)
#define sortr(x) sort(all(x),greater<int>())

using vi = vector <int>;
using vii = vector <vi>;
using viii = vector <vii>;
using pii = pair<int,int>;
using vpii = vector<pii>;

int res = 0;

void pre(){
 
}
 
void solve(){
	int n;cin >> n;
	vi vec(n);
	map<int,int> freq;
	for (int right  = 0, left = 0; right < n ; ++right) {
		cin >> vec[right];
		freq[vec[right]]++;
		while(freq[vec[right]] > 1) freq[vec[left++]]--;
		res = max(res, right - left + 1);
	}
	cout << res << endl;
}
 
signed main(){
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cout.tie(nullptr);
	// pre();
	solve();
}