#include <stdio.h>
#include <stdlib.h>

int inscal(int x,int y,int l);
int main()
{
    int x,y,l;
    int instruction=0;
    int absx,absy;
    
    scanf("%d%d%d",&x,&y,&l);
    
    absx=abs(x);
    absy=abs(y);
    
    instruction=inscal(absx,absy,l);
    if(y>0){
        if(x==0);
        else{
        instruction++;
        }
    }
    else if(y<0){
        instruction+=2;
    }
    else{
        if(x!=0){
            instruction++;
        }
        else{
            instruction=0;
        }
    }
    printf("%d\n",instruction);
    return 0;
}

int inscal(int x,int y,int l)
{
    int instruction=0;
    if(x%l==0){
        instruction+=x/l;
    }
    else{
        instruction+=x/l+1;
    }
      
    if(y%l==0){
        instruction+=y/l;
    }
    else{
        instruction+=y/l+1;
    }
    return instruction;
}