public class Main {

    boolean isPalindrome(int x) {
        if (x < 0)
            return false;
        int div = 1;
        while (x / div >= 10) {
            div *= 10;
        }
        while (x != 0) {
            int l = x / div;
            int r = x % 10;
            if (l != r)
                return false;
            x = (x % div) / 10;
            div /= 100;
        }
        return true;
    }


    public static void main(String[] args) {
        int i = 10000;
        int ii = 10000;
        int largest = 0;
        Main a = new Main();
        for(;i <= 99999;i++)
        {
            for(;ii <= 99999; ii++)
            {
                int iii = i * ii;
                //System.out.println(iii);
                if(a.isPalindrome(iii))
                    if(iii>largest)
                        largest = iii;
                }
            ii = 10000;
            }
        System.out.println(largest);
        }
    }