#include <iostream>
#include <vector>
#include <cmath>
#include <map>
#include <set>
#include <iomanip>
#include <queue>
#include <algorithm>
#include <numeric>
#include <deque>
#include <complex>
#include <cassert>

using namespace std;

int main(){

    int mi=2e9+100, cnt, d, s, use;
    vector<int> a(3), b;
    cin >> d;
    for (int i=0; i<3; i++) cin >> a[i];

    if (d == 0){
        if (a[0] != a[2] && a[0] < a[1] && a[1] > a[2]) cout << 0 << endl;
        else if (a[0] != a[2] && a[0] > a[1] && a[1] < a[2]) cout << 0 << endl;
        else cout << -1 << endl;
        return 0;
    }

    b=a; cnt=0;
    if (b[0] == b[2]){
        cnt=1;
        b[0] = max(0, b[0]-d);
    }
    s = min(b[0], b[2]);
    use = max(0, (b[1]-s+1+d-1)/d);
    b[1] = max(0, b[1]-use*d);
    cnt += use;
    if (b[0] != b[1] && b[1] != b[2]) mi = min(mi, cnt);

    b=a; cnt=0;
    use = max(0, (b[0]-b[1]+1+d-1)/d);
    b[0] = max(0, b[0]-use*d);
    cnt += use;
    use = max(0, (b[2]-b[1]+1+d-1)/d);
    b[2] = max(0, b[2]-use*d);
    cnt += use;
    if (b[0] == b[2]){
        cnt++;
        b[0] = max(0, b[0]-d);
    }
    if (b[0] != b[2]) mi = min(mi, cnt);

    cout << (mi == 2e9+100 ? -1 : mi) << endl;

    return 0;
}