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

// macros
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)
#define MIN(a,b) (a>b?b:a)
#define MAX(a,b) (a>b?a:b)
#define INT_IN(a) int a; cin >> a
#define STR_IN(s) string s; cin >> s
#define PRINTLN(s) cout << s << endl
#define PRINTDOUBLELN(s) cout << setprecision(12) << (s) << endl;

// util functions
template<class T> inline T sqr(T x) {return x*x;}

inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;}
template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();}

template <typename T>inline T max(vector<T> v){T max=v[0]; FOR(i, 1, v.size())max=MAX(v[i], max); return max;}
template <typename T>inline T min(vector<T> v){T min=v[0]; FOR(i, 1, v.size())min=MIN(v[i], min); return min;}
template <typename T>inline vector<T> concat(vector<T> a, vector<T> b){vector<T> ab; ab.reserve(a.size()+b.size());ab.insert(ab.end(),a.begin(),a.end());ab.insert(ab.end(),b.begin(),b.end());return ab;}

// types
typedef long long LL;

// consts
const double EPS = 1e-10;
const double PI  = acos(-1.0);

//debug
#define dump(x)  cerr << #x << " = " << (x) << endl
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl

int main(){
    INT_IN(X);
    INT_IN(Y);
    INT_IN(L);
    int cmdN = 0;
    int dX = ceil(1. * X / L);
    int dY = ceil(1. * Y / L);
    if(dX != 0) cmdN++;
    if(dY != 0) cmdN++;
    PRINTLN(dX + dY + cmdN);

    return 0;
}