#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;
using ll = long long;
using ld = long double;

#define all(x)  x.begin(),x.end()
#define v(x) vector<x>
#define nl '\n'
#define fxd(x) fixed << setprecision(x)
template<class t> using ordered_set = tree<t, null_type, less<t>, rb_tree_tag, tree_order_statistics_node_update>;
template<class t> using ordered_multiset = tree<t, null_type, less_equal<t>, rb_tree_tag, tree_order_statistics_node_update>;


int main()
{
    ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
    int n ; cin >> n;
    v(ll) arr(n); for (int i = 0; i < n; i++) cin >> arr[i];
    
    ll l =0 , r =0 , mxlen = 0;
    // val,freq
    map<ll,ll>mp;
    for (int r = 0; r < n; r++)
    {
        mp[arr[r]]++;
        if(mp[arr[r]] == 1)
        {
            mxlen = max(mxlen,r-l+1);
        }
        else
        {
            while (mp[arr[r]] > 1)
            {
                mp[arr[l++]]--;
            }
            
        }
    }
    cout << mxlen;
}