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