r=x-p[x]?x=p[x],r:x
f='h*=a[i]-a[x+=i]||(p[x=i,u=r]=r)-u'
p=({0..9999})
read w h
read -dx -aa
for((;x=i<w*h;~i%w&&f,x=w,f,++i)){ :;}
im
echo ${_[!h]}possible