#include <bits/stdc++.h>
using namespace std;

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int X,Y,L; cin >> X >> Y >> L;
    int answer = 0;
    if(X == 0 && Y == 0){cout << 0 << endl; return 0;}
    if(X == 0 && Y >= 0) answer += 0;
    else if(Y >= 0) answer += 1;
    else answer += 2;
    
    answer += (abs(X)+L-1)/L;
    answer += (abs(Y)+L-1)/L;
    cout << answer << endl;
}