#define REP(i, n) for(int i = 0;i < n;i++)
#define REPR(i, n) for(int i = n;i >= 0;i--)
#define FOR(i, m, n) for(int i = m;i < n;i++)

#include <iostream>
#include <string>
#include <algorithm>
using namespace std;
int main() {
	int ans,a,b,x;
	ans=0;
	cin >> a >> b >> x;
	if(b < 0) ans += 2;
	else if (a != 0) ans += 1;	

	ans+=abs(a)/x + abs(b)/x;
	if(a%x != 0) ans+=1;
	if(b%x != 0) ans +=1;
	cout << ans << endl;
	return 0;
}