import java.util.Scanner;
class robotto{
	public static void main(String args[]){
		Scanner s = new Scanner(System.in);
		int x = s.nextInt();
		int y = s.nextInt();
		int L = s.nextInt();
		int xtime = (int)Math.abs(x / L);
		int ytime = (int)Math.abs(y / L);
		int retur = 0;
		if(x != 0 && y >= 0){
			retur = 1;
		}else if(y < 0){
			retur = 2;
		}
		
		if(x % L != 0){
			xtime += 1;
		}
		if(y % L != 0){
			ytime += 1;
		}
		System.out.println(xtime + ytime + retur);
	}
}