x = gets.to_i.abs
y = gets.to_i.abs
l = gets.to_i

command = 0

if x != 0 && y != 0
    command += 1
end

case x
when 0
else
    if x % l == 0
        command += x / l
    else
        command += x / l + 1
    end
end

case y
when 0
else
    if y % l == 0
        command += y / l
    else
        command += y / l + 1
    end
end

puts command