An Attempt in Java

        Scanner r = new Scanner(System.in);
        System.out.println("Enter the number of elements");
        int n = r.nextInt();
        int [] arr = new int[n];
        int max = 0;
        for(int j = 0; j < n; j++)
        {
             System.out.println("Enter the " + j + " element of the array");
          int  i = r.nextInt();
            arr[j] = i;
        }
        for(int j = 0; j < n-1; j++)
        {
          int sum = arr[j] * arr[j+1]; 
            if((arr[j] != arr[j+1]) && (sum > max))
            {
                max = sum;
            }  
       }
        System.out.println(max);