import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int[] arr = new int[n];
        HashSet<Integer> exist = new HashSet<>();
        int left = 0;
        int max = 0;
        for (int i = 0; i < n; i++) {
            arr[i] = sc.nextInt();
            if (exist.contains(arr[i])) {
                while (arr[left] != arr[i]) {
                    exist.remove(arr[left]);
                    left++;
                }
                left++;
            } else {
                exist.add(arr[i]);
                max = Math.max(max, i - left + 1);
            }
        }
        System.out.println(max);
    }
}