package main

import . "fmt"
import . "math/big"

func main() {
	var h,s string
	Scan(&h,&s)
	bh,_:=new(Int).SetString(h,10)
	bs,_:=new(Int).SetString(s,10)
	m:=bh.Sub(bh,bs).Abs(bh).Mod(bh,NewInt(2)).Int64()
	
	if m==1 {
		Println("Impossible")
	} else {
		Println("Possible")
	}
}