while($0 <= H * W)
  $1 = A[$0/W+1,$0%W+1] - B[$0/W+1,$0%W+1]
  $1 = $1 * $1 + 998244352
  $1 = 1 - $1 / 998244353
  $0 = $0 + $1
end
return($0/W+1,$0%W+1)