#include <iostream>
#include <vector>
#include <string>
#include <cstring>
#include <math.h>
#include <cmath>
#include <limits.h>
#include <map>
#include <set>
#include <queue>
#include <algorithm>
#include <functional>
#include <stdio.h>
using namespace std;

long long MOD = 1000000007;

int main() {
    
    long long ans = 0;
    long long X,Y,L;
    cin >> X >> Y >> L;
    
    long long x = abs(X);
    long long y = abs(Y);
    
    ans += x/L + ( x%L ? 1 : 0 ) + y/L + ( y%L ? 1 : 0 );
    
    ans += Y >= 0 ? 0 : 1;
    ans += X == 0 && Y >= 0 ? 0 : 1;
    
    cout << ans << endl;
    
    return 0;
}