#include <bits/stdc++.h>
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define FFOR(i,a,b) for(int i=(a);i<=(b);i++)
#define REP(i,b) FOR(i,0,b)
#define RREP(i,b) FFOR(i,1,b)
#define PB push_back
#define F first
#define S second
#define BE(c) c.begin(),c.end()
using namespace std;
typedef long long LL;
typedef int ut;
typedef long double ld;
typedef pair<ut,ut> pr;
typedef vector<pr> Vpr;
typedef vector<ut> VI;
typedef pair<ut,pr> ppr;
typedef vector<ppr> Vppr;
typedef priority_queue<pr,Vpr,greater<pr> > PQ;
typedef priority_queue<ppr,Vppr,greater<ppr> > PprQ;
const int SIZE=5+3*1e+5;
const LL INF=1LL<<60;
const ld eps=1e-6;
const LL p=7+1e+9;
LL nums[SIZE];
int main(){
	string s;
	LL d,H[3];
	cin >> d;
	REP(i,3)
		cin >> H[i];
	LL ans=INF;
	if(H[1]<min(H[2],H[0]) || H[1]>max(H[2],H[0])) {
		cout << 0 << endl;
		return 0;
	}
	if(d==0 || (H[0]==0 && H[2]==0)){
		cout << -1 << endl;
		return 0;
	}
	ans=min(ans,(H[1]-min(H[0],H[2]))/d+1);
	ans=min(ans,max(0LL,H[2]-H[1]+d)/d+max(0LL,H[0]-H[1]+d)/d);
	cout << ans << endl;
	return 0;
}