Pernilla, Winterfolk Leader

Snow landwalk (This creature can't be blocked as
long as defending player controls a snow land.)
Pernilla, Winterfolk Leader gets +1/+0 for each
Snow-Covered Mountain you control.
Pernilla, Winterfolk Leader gets +0/+1 for each
Snow-Covered Plains you control.
Whenever Pernilla attacks, create X 1/1 red and
white Winterfolk tokens, where X is Pernilla's
power.