#include <iostream>
#include<utility>
#include <vector>
#include <map>
#include<string>
#include<queue>
#include<math.h>
#define pb push_back
#define all(x) begin(x),end(x)
#define ll long long
#define P pair<int,int>
#define lP pait<ll,ll>
using namespace std;
int main() {
    ll x,y,l,cnt=0;
    cin>>x>>y>>l;
    if(x==0){
        if(y<0) cnt+=1;
    }
    else {
        if(y==0) cnt++;
        else if(y>0) cnt++;
        else cnt+=2;
    }
    if(x%l==0) {
        cnt+=abs(x/l);
        if(y%l==0) cnt+=abs(y/l);
        else cnt+=abs(y/l)+1;
    }
    else{
        cnt+=abs(x/l)+1;
        if(y%l==0) cnt+=abs(y/l);
        else cnt+=abs(y/l)+1;
    }
    cout<<cnt<<endl;
    return 0;
}