#include <iostream>
#include <algorithm>
#include <vector>
#include <string>
#include <cmath>
#include <iomanip>
#include <map>
using namespace std;
typedef long long LL;

LL iabs(LL n){
    if(n < 0) return -n;
    return n;
}

int main(){
    LL x, y, L;
    cin >> x >> y >> L;
    LL ans = (iabs(x)+L-1)/L + (iabs(y)+L-1)/L;
    if(y >= 0){
        if(x != 0) ans++;
    }else{
        ans += 2;
    }
    cout << ans << endl;
    return 0;
}