#include <bits/stdc++.h>
#define rep(i, a) rep2 (i, 0, a)
#define rep2(i, a, b) for (int i = (a); i < (b); i++)
#define repr(i, a) repr2 (i, 0, a)
#define repr2(i, a, b) for (int i = (b) - 1; i >= (a); i--)
#define chmin(a, b) ((b) < a && (a = (b), true))
#define chmax(a, b) (a < (b) && (a = (b), true))
#define rng(a) (a).begin(), (a).end()
using namespace std;
typedef long long ll;

int main() {
	ll d, h1, h2, h3;
	cin >> d >> h1 >> h2 >> h3;
	if (h1 < h2 && h2 > h3)	{
		cout << 0 << endl;		
		return 0;
	}
	if (h1 > h2 && h2 < h3) {
		cout << 0 << endl;
		return 0;
	}
	const ll inf = 1e18;
	auto f = [&](ll a, ll b) { 
		if (a < b) return 0ll;
		return (a - b + d) / d; 
	};
	auto g = [&](ll a) {
		return max(0ll, a - d);
	};
	ll ans = inf;
	{
		ll th1 = h1;
		if (th1 == h3) th1 = g(th1);
		ll cand = f(h2, min(th1, h3));	
		ll th2 = max(0ll, h2 - cand * d);
		if (th1 == th2 || th2 == h3) cand = inf;
		cerr << cand << endl;
		chmin(ans, cand);
	}
	{
		ll c1 = f(h1, h2);
		ll c3 = f(h3, h2);
		h1 = max(0ll, h1 - c1 * d);
		h3 = max(0ll, h3 - c3 * d);
		cerr << h1 << " " << h2 << " " << h3 << endl;
		ll cand = c1 + c3;
		if (h1 == h3) {
			if (g(h1) != h3) cand++;
			else cand = inf;
		} 
		cerr << cand << endl;
		chmin(ans, cand);
	}
	if (ans >= inf) ans = -1;
	cout << ans << endl;
}