#include <bits/stdc++.h>

#define ll long long
#define ld long double
#define rep(i,a,b) for (int i = a; i < b; i++)
#define irep(i,a,b) for (int i = a; i > b; i--)
#define print(n) cout << n << endl
#define rup(a,b) (a+b-1)/b

using namespace std;

int main(){
    cout << fixed << setprecision(15);
    
    ll X,Y,L;
    swap(X,Y);
    cin >> X >> Y >> L;
    swap(X,Y);
    ll count = 0;
    if(!(Y == (ll)0)){
        if (X>= 0) count += 1;
        else count += 2;
    }else{
        if (X>=0) count += 0;
        else count += 2;
    }
    count += rup(abs(X),L);
    count += rup(abs(Y),L);
    print(count);
    
    //system("pause");
    return 0;
}