orders has columns order_id and product.

Return the product ordered most often as a Series of product names sorted alphabetically, with the index renumbered from 0. If several products tie for the most orders, return all of them.

Input

   order_id product
0         1     pen
1         2     pen
2         3     ink
3         4     ink
4         5     pad
5         6     pen

Output

0    pen
dtype: object