/*No.48 ロボットの操縦*/
import java.util.*;
public class No48 {
	static int Order=0;
	static int walk(int TargetPoint,int WalkSpec){
		int work=Math.abs(TargetPoint);
		if(TargetPoint%WalkSpec==0){
			Order+=work/WalkSpec;
			return TargetPoint/WalkSpec;
		}else{
			work/=WalkSpec;
			Order+=work+1;
			return work*WalkSpec+Math.abs(TargetPoint%WalkSpec);	
		}
	}
	public static void main(String[] args) {
		int TargetX,TargetY,WalkSpec,CurrentX=0,CurrentY=0;
		try(Scanner input = new Scanner((System.in))){
			TargetX=input.nextInt();
			TargetY=input.nextInt();
			WalkSpec=input.nextInt();
			if(TargetY<0){
				Order++;
				if(TargetX!=0)
					CurrentX=walk(TargetX,WalkSpec);
				if(TargetY!=0){
					Order++;
					CurrentY=walk(TargetY,WalkSpec);					
				}
			}else{
				CurrentY=walk(TargetY,WalkSpec);
				if(TargetX!=0){
					Order++;
					CurrentX=walk(TargetX,WalkSpec);
				}
			}
			System.out.println(Order);
		}catch(Exception e){
			e.printStackTrace();
		}
	}
}