$510840120140425 = 0;
while(A[$510840120140425/W+1][$510840120140425%W+1] == B[%510840120140425/W+1][$510840120140425%W+1])
    $510840120140425 = $510840120140425+1;
end
return($510840120140425/W+1,$510840120140425%W+1)