A severe egg shortage has struck the country, causing panic buying and supply disruptions. With supermarkets limiting purchases, you need to collect all different types of specialty eggs (organic, free-range, omega-3 enriched, etc.) for your bakery business.

There are supermarkets nearby, each stocking different varieties. The -th supermarket carries distinct egg types, listed as . Due to rationing and long queues, you want to minimize the number of supermarkets you visit while ensuring you obtain every required egg variety.

First line: Two integers  (total distinct egg types needed, ) and  (number of supermarkets, ).

Each of the next  lines describes a supermarket's egg selection. The first integer is  (number of egg types available of the -th supermarket, ), then  distinct integers  () follow.

A single integer: the minimum number of supermarkets required to obtain all  egg types. If some types are unavailable, output .

5 3
3 1 2 3
2 2 4
3 3 4 5

2

2 1
1 1

-1