import java.io.*;

class Main {

    static int N = 100010;
    static int n, maxLen;
    static int[] a = new int[N];

    static int head, tail;
    static int[] queue = new int[N];
    static boolean[] isIn = new boolean[N];

    public static void main(String[] args) throws IOException {
        InputStreamReader isr = new InputStreamReader(System.in);
        BufferedReader in = new BufferedReader(isr);
        n = Integer.parseInt(in.readLine());
        String[] strs = in.readLine().split(" ");
        for (int i = 1; i <= n; i++) a[i] = Integer.parseInt(strs[i - 1]);
        in.close();
        isr.close();

        OutputStreamWriter osw = new OutputStreamWriter(System.out);
        BufferedWriter out = new BufferedWriter(osw);

        for (int i = 1; i <= n; i++) {
            if (isIn[a[i]]) {
                for (int x = queue[head]; x != a[i]; ) {
                    isIn[x] = false;
                    x = queue[++head];
                }
                head++;
            }
            queue[tail++] = a[i];
            isIn[a[i]] = true;
            maxLen = Math.max(maxLen, tail - head);
        }
        out.write(maxLen + "");
        out.flush();
        out.close();
        osw.close();
    }
}