$0=0
while($0<H*W)
    if(A[$0 / W + 1,$0 % W + 1] != B[$0 / W + 1,$0 % W + 1])
        $1 = $0 / W +1
        $2 = $0 % W +1
    $0 = $0 + 1
end
return($1,$2)