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

// Macro Tools /////////////////////////////////////////////////////////////////
#define GET_MACRO_09(A1, A2, A3, A4, A5, A6, A7, A8, A9, NAME, ...) NAME

#define EXPAND_01(FIRST, NEXT, A) \
	FIRST(A)
#define EXPAND_02(FIRST, NEXT, A, B) \
	FIRST(A) NEXT(B)
#define EXPAND_03(FIRST, NEXT, A, B, C) \
	FIRST(A) NEXT(B) NEXT(C)
#define EXPAND_04(FIRST, NEXT, A, B, C, D) \
	FIRST(A) NEXT(B) NEXT(C) NEXT(D)
#define EXPAND_05(FIRST, NEXT, A, B, C, D, E) \
	FIRST(A) NEXT(B) NEXT(C) NEXT(D) NEXT(E)
#define EXPAND_06(FIRST, NEXT, A, B, C, D, E, F) \
	FIRST(A) NEXT(B) NEXT(C) NEXT(D) NEXT(E) NEXT(F)
#define EXPAND_07(FIRST, NEXT, A, B, C, D, E, F, G) \
	FIRST(A) NEXT(B) NEXT(C) NEXT(D) NEXT(E) NEXT(F) NEXT(G)
#define EXPAND_08(FIRST, NEXT, A, B, C, D, E, F, G, H) \
	FIRST(A) NEXT(B) NEXT(C) NEXT(D) NEXT(E) NEXT(F) NEXT(G) NEXT(H)
#define EXPAND_09(FIRST, NEXT, A, B, C, D, E, F, G, H, I) \
	FIRST(A) NEXT(B) NEXT(C) NEXT(D) NEXT(E) NEXT(F) NEXT(G) NEXT(H) NEXT(I)
#define EXPAND_ADD(FIRST, NEXT, ...) \
	GET_MACRO_09(__VA_ARGS__, EXPAND_09, EXPAND_08, EXPAND_07, EXPAND_06, \
		EXPAND_05, EXPAND_04, EXPAND_03, EXPAND_02, EXPAND_01) \
	(FIRST, NEXT, __VA_ARGS__)
#define EXPAND(MACRO, ...) EXPAND_ADD(MACRO, MACRO, __VA_ARGS__)

#define Q(x) #x
#define QUOTE(x) Q(x)

// Input ///////////////////////////////////////////////////////////////////////
#define RIGHT_SHIFT_BEFORE(a) >>a
#define CAMMA_AND_ADDRESS(a) , &a
#define INT_FORMATTER(a) %d
#define SCANF_INT(a) scanf("%d", &(a));
// #define SCANF_LL(a) scanf("%I64d", &(a));

#define I(...) int __VA_ARGS__; EXPAND(SCANF_INT, __VA_ARGS__);
// #define L(...) long long __VA_ARGS__; EXPAND(SCANF_LL, __VA_ARGS__);

#define input(t,v) t v;cin>>v;
#define input2(t,v1,v2) t v1,v2;cin>>v1>>v2;
#define input3(t,v1,v2,v3) t v1,v2,v3;cin>>v1>>v2>>v3;

#if __cplusplus > 199711L  //C++11
template<class T=int>
#else
template<class T>
#endif
T read() {
	T t;
	cin >> t;
	return t;
}

// Types ///////////////////////////////////////////////////////////////////////
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef set<int> si;
typedef set<ll, ll> sll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef list<int> li;
typedef list<ll> lll;
typedef map<int, int> mii;
typedef map<int, ll> mil;
typedef map<ll, int> mli;
typedef map<ll, ll> mll;

// Loop & Iteration ////////////////////////////////////////////////////////////
#define FOR(i, a, b) for(int i = (a), loop_end_##i=(b); i < (loop_end_##i); i++)
#define REP(i, n) FOR(i, 0, n)
#define rep(v,n) for(int (v)=0;(v)<(n);(v)++)
#define EACH(i,c) for(auto i=(c).begin(); i!=(c).end(); ++i)
#define SORT(c) sort((c).begin(),(c).end())
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define PB push_back

// Range ///////////////////////////////////////////////////////////////////////
#define IN(x, a, b) (a<=x && x<b)
int dx[8] = { 1, 0, 0,-1, 1, 1,-1,-1};
int dy[8] = { 0,-1, 1, 0,-1, 1,-1, 1};

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

////////////////////////////////////////////////////////////////////////////////

int main(){
	I(d, h1, h2, h3);
	if((h1==0 && h2==0) || (h2==0 && h3==0) || (h1==0 && h3==0)){
		printf("-1\n");
		return 0;
	}
	if(((h1>h2 && h2<h3) || (h1<h2 && h2>h3)) && h1!=h3){
		printf("0\n");
		return 0;
	}
	if(d==0){
		printf("-1\n");
		return 0;
	}
	if((h1==0 && h2<=d && h3<=d) || (h1<=d && h2<=d && h3==0)){
		printf("-1\n");
		return 0;
	}
	int ans0=0;
	if(h1==h3){
		ans0=1;
		if(h1>0) h1=max(0, h1-d);
		if(h3>0) h3=max(0, h3-d);
	}
	int ans1=INT_MAX;
	if (min(h1, h3)){
		int low = min(h1, h3)-1;
		ans1=(h2-low+d-1)/d;
	}
	int ans2=INT_MAX;
	ans2=(max(h1, h3)-(h2-1)+d-1)/d;
	printf("%d\n", ans0+min(ans1, ans2));
}