#include<stdio.h>

int main(){
    int x,y,l;
    scanf("%d",&x);scanf("%d",&y);scanf("%d",&l);
    int res = 0;

    if(y < 0)
        res += 2;
    if(x != 0)
        res += 1;

    x = (x < 0)?(-1)*x:x;
    y = (y < 0)?(-1)*y:y;

    res += (x%l == 0)?x/l:(x/l)+1;
    res += (y%l == 0)?y/l:(y/l)+1;

    printf("%d\n",res);

    return 0;
}