#include<bits/stdc++.h>
using namespace std;
using Int = long long;
template<typename T1,typename T2> inline void chmin(T1 &a,T2 b){if(a>b) a=b;}
template<typename T1,typename T2> inline void chmax(T1 &a,T2 b){if(a<b) a=b;}

//INSERT ABOVE HERE

const Int INF = 1e15;
// a < b > c
Int solve1(Int a,Int b,Int c,Int d){
  if(b<2) return INF;
  if(d==0) return a<b&&b>c&&a!=c?0:INF;
  Int res=0;
  if(a>=b){
    Int x=(a-b)/d;
    a-=x*d;res+=x;
    if(a>=b) a-=d,res++;
  }
  if(c>=b){
    Int x=(c-b)/d;
    c-=x*d;res+=x;
    if(c>=b) c-=d,res++;
  }
  chmax(a,0);
  chmax(c,0);
  // a < b > c
  assert(a<b&&b>c);
  if(a==0&&c==0) return INF;
  if(a!=c) return res;
  return res+1;
}
// a > b < c
Int solve2(Int a,Int b,Int c,Int d){
  if(min(a,c)<=0) return INF;
  if(d==0) return a>b&&b<c&&a!=c?0:INF;
  Int res=0;
  if(min(a,c)<=b){
    Int x=(b-min(a,c))/d;
    b-=x*d;res+=x;
    if(min(a,c)<=b) b-=d,res++;
  }
  chmax(b,0);
  assert(a>b&&b<c);
  // a > b < c
  if(a!=c) return res;
  return solve2(a-d,b,c,d)+res+1;  
}
signed main(){
  Int d,a,b,c;
  cin>>d>>a>>b>>c;
  Int ans=min(solve1(a,b,c,d),solve2(a,b,c,d));
  if(ans>=INF) ans=-1;
  cout<<ans<<endl;
  return 0;
}