#include <iostream>
#include <vector>
#include <cstring>
#include <algorithm>
#include <fstream>
#include <map>
#include <stack>
using namespace std;
typedef long long ll;
const int INF = 1e9;

int main()
{
    ios_base::sync_with_stdio(false);
//    ifstream cin("in.txt");
    int n;
    cin >> n;
    vector<int> v(n);
    for(int i = 0; i < n; i++) {
        cin >> v[i];
    }
    map<int, int> cnt;
    int L = 0, R = 0;
    int current_length = 0;
    int ans = 0;
    while(R < n) {
        if(cnt.find(v[R]) == cnt.end() or cnt[v[R]] == 0) {
            cnt[v[R]] += 1;
            current_length += 1;
            ans = max(ans, current_length);
            R += 1;
        }
        else {
            current_length -= 1;
            cnt[v[L]] -= 1;
            L += 1;
        }
    }
    cout << ans << endl;
    return 0;
}
/*
 mapa<int, int> m;
 1 2 1 3 2 i7 4 2j
 */