#include <iostream>
#include <cmath>
using namespace std;
#define rep(i,n) for(int i = 0; i < (n); i++)

int main(){
    int x = 0; cin >> x;
    int y = 0; cin >> y;
    int l = 0; cin >> l;
    int mo = 0;
    int res = 0;

    if(y<0){ mo = y/l; res=y%l; if(res!=0){ mo+=1; }}
    else if(y>0){ y = abs(y); mo+=1; mo+=y/l; res=y%l; if(res!=0){ mo+=1; }}

    if(x<0){ mo+=1; mo+=x/l; res=y%l; if(res!=0){ mo+=1; }}
    else if(x>0){ x = abs(x); mo+=1; mo+=x/l; res=y%l; if(res!=0){ mo+=1; }}

    cout << mo << endl;
    return 0;
}