CD exchange
In a computer club, there is a CD disc exchange market where you can trade any disc for another one from the catalog, either directly or through a series of intermediate exchanges. The catalog features N different discs, numbered from 1 to N. For each disc i in the catalog (i=1..N), there is a list of disc numbers that you can obtain in exchange, with an additional cost of 1 UAH for each exchange.
Determine the minimum amount of UAH required to acquire all the discs, given that you already have an unlimited supply of the first K discs in the catalog.
Input Data
The first line of the input contains the integers N and K. The following N lines provide information about the possible exchanges for each disc i.
Output Data
Output the minimum amount of UAH needed to exchange for all the discs in the catalog. All numbers are natural numbers and do not exceed 100.