$0 = 0
$4 = 0
while ($0 < H * W)
  $1 = A[$0/W+1, $0%W+1]
  $2 = B[$0/W+1, $0%W+1]
  $3 = ($1 - $2) * ($1 - $2)
  $3 = ($3 + 10000) / 10001
  $4 = $4 + $0 * $3
  $0 = $0 + 1
end
return ($4/W+1, $4%W+1)