#include<stdio.h>

int walk(int to,int l){
    if(to%l==0){
        return to/l;
    }else{
        return to/l+1;
    }
}

int main(){
    int x;
    int y;
    int l;
    scanf("%d%d%d",&x,&y,&l);
    int step=0;
    if(y>0){
        step+=walk(y,l);
        
        if(x>0){
            step++;
            step+=walk(x,l);
        }else if(x<0){
            step++;
            step+=walk(-x,l);
        }
    }else if(y<0){
        step++;
        if(x>0){
            step+=walk(x,l);
        }else if(x<0){
            step+=walk(-x,l);
        }
        step++;
        step+=walk(-y,l);
    }else{
        step++;
        if(x>0){
            step+=walk(x,l);
        }else if(x<0){
            step+=walk(-x,l);
        }
    }
    printf("%d",step);
}