#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>

#define FORR(i,b,e) for(int i=(b);i<(int)(e);++i)
#define FOR(i,e) FORR(i,0,e)
#define sortuniq(v) sort(v.begin(), v.end()), v.erase(unique(v.begin(),v.end()),v.end())
#define dump(var) cerr << #var ": " << var << "\n"
#define dumpc(con) for(auto& e: con) cerr << e << " "; cerr<<"\n"

typedef long long ll;
typedef unsigned long long ull;

const double EPS = 1e-6;
const int d4[] = {0, -1, 0, 1, 0};

using namespace std;


int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    int d;
    cin >> d;

    vector<int> h(3);
    int s, ss=1e9+1, l, ls=-1;
    FOR(i, 3) {
        cin >> h[i];
        if (h[i] < ss) {
            ss = h[i];
            s = i;
        }
        if (h[i] > ls) {
            ls = h[i];
            l = i;
        }
    }
    
    if (s == 1 || l == 1) {
        cout << 0 << endl;
    }
    else if (d == 0) {
        cout << -1 << endl;
    }
    else if (h[s] == 0 && h[1] == 0) {
        cout << -1 << endl;
    }
    else if (h[s] == 0) {
        int n = (h[l]-h[1])/d + 1;
        int xl = max(0, h[l] - n*d);
        if (xl == 0) cout << -1 << endl;
        else {
            cout << n << endl;
        }
    }
    else {
        int mind = min(h[1]-h[s], h[l]-h[1]);
        cout << mind/d + 1 << endl;
    }

    return 0;
}