#include <stdio.h>
#include <stdlib.h>
int main(){
    //iuput
    int X,Y,L;
    scanf("%d %d %d",&X,&Y,&L);

    //output
    int count = 0;

    //turn
    if (X == 0){
        if (Y < 0){
            count += 2;
        }else{
            count += 0;
        }
    }else{
        if (Y < 0){
            count += 2;
        }else{
            count += 1;
        }
    }

    //step
    X = abs(X);
    Y = abs(Y);
    if (X%L == 0){
        count += X/L;
    }else{
        count += (X-X%L)/L+1;
    }
    if (Y%L == 0){
        count += Y/L;
    }else{
        count += (Y-Y%L)/L+1;
    }

    //output
    printf("%d\n",count);

    return 0;
}