#include <cstdlib>
#include <cmath>
#include <climits>
#include <cfloat>
#include <map>
#include <set>
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <sstream>
#include <complex>
#include <stack>
#include <queue>
#include <cstdio>
#include <cstring>
#include <iterator>
#include <bitset>
#include <unordered_set>
#include <unordered_map>
#include <fstream>
#include <iomanip>
//#include <utility>
//#include <memory>
//#include <functional>
//#include <deque>
//#include <cctype>
//#include <ctime>
//#include <numeric>
//#include <list>
//#include <iomanip>

//#if __cplusplus >= 201103L
//#include <array>
//#include <tuple>
//#include <initializer_list>
//#include <forward_list>
//
//#define cauto const auto&
//#else

//#endif

using namespace std;


typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

typedef vector<int> vint;
typedef vector<vector<int> > vvint;
typedef vector<long long> vll, vLL;
typedef vector<vector<long long> > vvll, vvLL;

#define VV(T) vector<vector< T > >

template <class T>
void initvv(vector<vector<T> > &v, int a, int b, const T &t = T()){
    v.assign(a, vector<T>(b, t));
}

template <class F, class T>
void convert(const F &f, T &t){
    stringstream ss;
    ss << f;
    ss >> t;
}

#undef _P
#define _P(...) (void)printf(__VA_ARGS__)
#define reep(i,a,b) for(int i=(a);i<(b);++i)
#define rep(i,n) reep((i),0,(n))
#define ALL(v) (v).begin(),(v).end()
#define PB push_back
#define F first
#define S second
#define mkp make_pair
#define RALL(v) (v).rbegin(),(v).rend()
#define DEBUG
#ifdef DEBUG
#define dump(x)  cout << #x << " = " << (x) << endl;
#define debug(x) cout << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;
#else
#define dump(x) 
#define debug(x) 
#endif
#define LDcout(x,n) fixed<<setprecision(n)<<x

#define MOD 1000000007LL
#define EPS 1e-8
#define INF 0x3f3f3f3f
#define INFL 0x3f3f3f3f3f3f3f3fLL
#define maxs(x,y) x=max(x,y)
#define mins(x,y) x=min(x,y)

void mainmain(){
	ll d;
	cin>>d;
	vll v(3);
	rep(i,3) cin>>v[i];
	vint p(3);
	rep(i,3){
		p[i]=i;
	}
	if(d==0){
		bool f=false;
		if(v[0]>v[1]&&v[1]<v[2]){
			if(v[0]!=v[2]) f=true;
		}
		else if(v[0]<v[1]&&v[1]>v[2]){
			if(v[0]!=v[2]) f=true;
		}
		if(f) cout<<0<<endl;
		else cout<<-1<<endl;
		return;
	}
	ll ans=INFL;
	do{
		ll tans=0;
		if(p[1]==1) continue;
		vll tmp(3);
		rep(i,3){
			tmp[i]=v[p[i]];
		}
		if(tmp[2]==0) continue;
		while(1){
			if(tmp[2]>tmp[1]-d*100000) break;
			tans+=100000;
			tmp[1]-=d*100000;
			// cout<<tmp[2]<<" "<<tmp[1]<<endl;
		}
		rep(i,110000){
			if(tmp[2]>tmp[1]) break;
			tans++;
			tmp[1]-=d;
		}
		if(tmp[1]<=0) continue;
		while(1){
			if(tmp[1]>tmp[0]-d*100000) break;
			tans+=100000;
			tmp[0]-=d*100000;
		}
		rep(i,110000){
			if(tmp[1]>tmp[0]) break;
			tans++;
			tmp[0]-=d;
		}
		ans=min(ans,tans);
	}while(next_permutation(ALL(p)));
	if(ans==INFL) ans=-1;
	cout<<ans<<endl;
}


signed main() {
	ios_base::sync_with_stdio(false);
    cin.tie(0);
  	cout<<fixed<<setprecision(20);
    mainmain();
}