#include <bits/stdc++.h>
using namespace std;
using i64 = int64_t;
using vi = vector<i64>;
using vvi = vector<vi>;

int main() {
    int d;
    int a, b, c;
    cin >> d >> a >> b >> c;
    if (a < b && b > c) {
        cout << 0 << endl;
        return 0;
    }

    if (a > b && b < c) {
        cout << 0 << endl;
        return 0;
    }

    if (d == 0 || b == 0) {
        cout << -1 << endl;
        return 0;
    }

    int ans = -1;
    int k = min(a, c);
    if (k != 0) {
        int diff = b - (k - 1);
        ans = (diff + d - 1) / d;
    }

    k = max(a, c);
    if (k != 0) {
        int diff = k - (b - 1);
        if (ans == -1) {
            ans = (diff + d - 1) / d;
        } else {
            ans = min(ans, (diff + d - 1) / d);
        }
    }
    cout << ans << endl;
}