#include <iostream>
#include <vector>
#include <map>
#define lli long long int
#define li long int
#define ld long double
using namespace std;

int main()
{
    int n;
    cin >> n;
    vector<int> arr(n);
    for (int i = 0; i < n; i++)
    {
        cin >> arr[i];
    }
    int i = 0, j = 0, max_len = 0, curr_len = 0;
    map<int, int> freq;
    while (j < n)
    {
        if (freq[arr[j]] == 0)
        {
            freq[arr[j]]++;
            curr_len++;
            max_len = max(max_len, curr_len);
            j++;
        }
        else
        {
            curr_len--;
            freq[arr[i]]--;
            i++;
        }
    }
    cout << max_len;
    return 0;
}