#include <bits/stdc++.h>
using namespace std;
/*{{{*/  //template
#define REP(i,n) for(int i=0;i<n;i++)
#define rep(i,n) for(int i=0;i<n;i++)
#define INF 1<<29
#define LINF LLONG_MAX/3
#define MP make_pair
#define PB push_back
#define EB emplace_back
#define ALL(v) (v).begin(),(v).end()
#define all(v) ALL(v)
#define debug(x) cerr<<#x<<":"<<x<<endl
#define debug2(x,y) cerr<<#x<<","<<#y":"<<x<<","<<y<<endl
#define CININIT cin.tie(0),ios::sync_with_stdio(false)
template<typename T> ostream& operator<<(ostream& os,const vector<T>& vec){ os << "["; for(const auto& v : vec){ os << v << ","; } os << "]"; return os; }
template<typename T,typename U> ostream& operator<<(ostream& os,const pair<T,U>& p){ os << "(" << p.first << ","<< p.second <<")"; return os; }
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;
ll gcd(ll a,ll b){ if(b==0) return a; else return gcd(b,a%b); }

constexpr ll mod = 1e9+7;
const int dx[]={1,0,-1,0} ,dy[] = {0,1,0,-1};
/*}}}*/

int main(){
    ll d;
    vector<ll> h(3);
    cin>>d;
    rep(i,3) cin>>h[i];

    if(h[0]==0 and h[1] == 0 and h[2]==0){
        cout << -1 << endl;
        return 0;
    }

    ll ans=0;
    if(h[0]==h[2]){
        ans++;
        h[2]-=d;
    }
    if(h[0]!=h[1] and h[1]!=h[2]){
        if(h[0]>h[1] and h[2]>h[1]){
            cout << ans << endl;
            return 0;
        }else if(h[0] > h[1] and h[1] > h[2]){
            cout << ans << endl;
            return 0;
        }
    }

    if(h[0] > h[2]) swap(h[0],h[2]);

    ll m = h[0]-1;
    ll d1 = ((h[1]-m)+d-1)/d;

    ll m2=h[1]-1;
    ll d2 = ((h[2]-m2)+d-1)/d;
    debug(h);
    debug2(d1,d2);
    cout << min(d1,d2)+ans << endl;
}