my $X = <>;
my $Y = <>;
my $K = <>;

#to make a positive number
my $pX = sqrt($X*$X);
my $pY = sqrt($Y*$Y);

my $remainder_x = $pX % $K;
my $count_x = ($pX - $remainder_x)/$K;

my $remainder_y = $pY % $K;
my $count_y = ($pY - $remainder_y)/$K;

my $count;

if($remainder_x != 0 && $remainder_y != 0){
    $count = 2;
}elsif($remainder_x != 0 || $remainder_y != 0){
    $count = 1;
}else{
    $count = 0;
}

my $turn;

if($X == 0 && $Y == 0){
    $turn = 0;
}elsif($X == 0 && $Y > 0){
    $turn = 0;
}elsif($Y < 0){
    $turn = 2;
}else{
    $turn = 1;
}

my $ans = $count + $count_x + $count_y + $turn;

print "$ans\n";