#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

#define RREP(i,s,e) for (i = s; i >= e; i--)
#define rrep(i,n) RREP(i,n,0)
#define REP(i,s,e) for (i = s; i < e; i++)
#define rep(i,n) REP(i,0,n)
#define INF 1e8

typedef long long ll;

int main() {
    int d, h1, h2, h3;
    cin >> d >> h1 >> h2 >> h3;
    if (h1 > h3)
        swap(h1,h3);
    if (h1 == 0 && h2 == 0 || h3 == 0)
        cout << -1 << endl;
    else if (h1 == h2 && h2 == h3) {
        if (h1 > d)
            cout << 3 << endl;
        else
            cout << -1 << endl;
    }
    else if (h1 == h3) {
        if (h1 < h2)
            cout << 1 << endl;
        else if (h1 < d)
            cout << -1 << endl;
        else if (h1 - d == h2) {
            if (h1 < 2*d)
                cout << -1 << endl;
            else
                cout << 2 << endl;
        }
        else
            cout << 1 << endl;

    }
    else if (h1 == h2) {
        if (d > 0 && h1 >= d)
            cout << 1 << endl;
        else
            cout << -1 << endl;
    }
    else if (h2 == h3) {
        if (h1 == h3 - d) {
            if (h3 > 2*d)
                cout << 2 << endl;
            else
                cout << -1 << endl;
        }
        else if (d > 0 && h3 >= d)
            cout << 1 << endl;
        else
            cout << -1 << endl;
    }
    else if ((h2 < h1 || h2 > h3))
        cout << 0 << endl;
    else if (d == 0)
        cout << -1 << endl;
    else {
        int x, y;
        x = (h2-h1)/d+1;
        if (h1 != max(0,h2 - x*d))
            x = (h2-h1)/d+1;
        else if (h1 != max(0,h2 - (x+1)*d))
            x++;
        else
            x = 1e9;
        y = (h3-h2)/d+1;
        if (h2 != max(0,h3 - y*d) && h1 != max(0,h3 - y*d))
            y = (h3-h2)/d+1;
        else if (h1 != max(0,h3 - (y+1)*d))
            y++;
        else if (h1 != max(0,h3 - (y+2)*d))
            y += 2;
        else
            y = 1e9;
        if (min(x,y) == 1e9)
            cout << -1 << endl;
        else
            cout << min(x,y) << endl;
    }
    return 0;
}