let X = abs(Int(readLine()!)!)
var Y = Int(readLine()!)
let L = Int(readLine()!)
var command = 0
command += Y! < 0 ? 2 : 0
Y = abs(Y!)
command += Y! / L!
command += (0 != (Y! % L!) ? 1 : 0)
command += (0 != X ? 1 : 0)
command += X / L!
command += (0 != (X % L!) ? 1 : 0)
print(command)