import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

class No48 {

	public static void main(String[] args) throws IOException, NumberFormatException{
		
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		int touzai = Integer.parseInt(br.readLine());
		int nanboku = Integer.parseInt(br.readLine());
		int zenshin = Integer.parseInt(br.readLine());
		
		int x = Calculation.calc(touzai,zenshin);
		int y = Calculation.calc(nanboku,zenshin);
		
		if (touzai != 0 && nanboku != 0) System.out.println(x+y+1);
		else System.out.println(x+y);
		
	}
	
	public static class Calculation{
		public static int calc(int x, int y){
			if (Math.abs(x)%y == 0) return (Math.abs(x)/y);
			else return (Math.abs(x)/y) + 1;
		}
	}
}