//48
#include <bits/stdc++.h>
#define rep(i ,n) for(int i=0;i<(int)(n);++i)
using namespace std;
typedef long long int int64;
typedef unsigned long long uint64;

int main(){
    int x , y , l;
    cin >> x >> y >> l;
    int turn;
    if( x > 0 && y > 0 ) turn = 1;
    else if( x < 0 && y > 0 ) turn = 1;
    else if( x < 0 && y < 0 ) turn = 2;
    else if( x > 0 && y < 0 ) turn = 2;
    else if( x == 0 && y > 0 ) turn = 0;
    else if( x == 0 && y < 0 ) turn = 2;
    else if( y == 0 && x > 0 ) turn = 1;
    else if( y == 0 && x < 0 ) turn = 1;
    int mov_x, mov_y;

    if( x % l == 0) mov_x = abs( x / l );
    else mov_x = abs( x / l ) + 1;
    if( y % l == 0) mov_y = abs( y / l );
    else mov_y = abs( y / l ) + 1;
    cout << turn + mov_x + mov_y << endl;
}