#include<iostream>
#include<vector>
#include<algorithm>
#include<cstdio>
#include<cmath>
using namespace std;
int main(){
    long long X,Y,L,ans=0;
    cin >> X >> Y >> L;
    if(Y<0){ 
        Y*=-1;
        if(X==0)    ans+=2;
        else    ans++;
    }
    if(X<0) X*=-1;
    if(X>0) ans++;
    if(Y>0) ans++;
    ans += ((X-1)/L)+((Y-1)/L)+1;
    cout << ans;
    return 0;
}