#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <queue>
#include <string>
#include <map>
#include <set>
#include <stack>
#include <tuple>
#include <deque>
#include <array>
#include <numeric>
#include <bitset>
#include <iomanip>
#include <cassert>
#include <chrono>
#include <random>
#include <limits>
#include <iterator>
#include <functional>
#include <sstream>
#include <fstream>
#include <complex>
#include <cstring>
#include <unordered_map>
#include <unordered_set>
using namespace std;

using ll = long long;
constexpr int INF = 1001001001;
constexpr int mod = 1000000007;
// constexpr int mod = 998244353;

template<class T>
inline bool chmax(T& x, T y){
    if(x < y){
        x = y;
        return true;
    }
    return false;
}
template<class T>
inline bool chmin(T& x, T y){
    if(x > y){
        x = y;
        return true;
    }
    return false;
}

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

    ll d;
    cin >> d;
    vector<ll> H(3);
    for(int i = 0; i < 3; ++i)  cin >> H[i];
    if(d == 0){
        bool ok = true;
        ok &= H[0] == H[1] || H[1] == H[2] || H[2] == H[0];
        ok &= max({H[0], H[1], H[2]}) == H[1] || min({H[0], H[1], H[2]}) == H[1];
        cout << (ok ? 0 : -1) << endl;
        return 0;
    }

    constexpr ll inf = 7e+18;
    ll ans = inf;

    // max = h1
    auto h = H;
    ll sum = 0;
    if(H[1] > 1){
        if(h[0] >= h[1]){
            sum += (abs(H[1] - 1 - H[0]) + d - 1) / d;
            h[0] = max(0LL, h[0] - (abs(H[1] - 1 - H[0]) + d - 1) / d * d);
        }
        if(h[2] >= h[1]){
            sum += (abs(H[1] - 1 - H[2]) + d - 1) / d;
            h[2] = max(0LL, h[2] - (abs(H[1] - 1 - H[2]) + d - 1) / d * d);
        }
        if(h[0] == h[2]){
            sum += 1;
            h[0] = max(0LL, h[0] - d);
        }
        if(h[0] != h[2])    chmin(ans, sum);
    }

    // min = h1
    h = H;
    sum = 0;
    if(h[0] == h[2]){
        sum += 1;
        h[0] = max(0LL, h[0] - d);
    }
    ll minv = min(h[0], h[2]);
    if(minv >= 1){
        if(h[1] >= minv){
            sum += (abs(minv - 1 - H[1]) + d - 1) / d;
            h[1] = max(0LL, h[1] - (abs(minv - 1 - H[1]) + d - 1) / d * d);
        }
        if(minv != h[1])    chmin(ans, sum);
    }

    if(ans == inf)  ans = -1;
    cout << ans << endl;

    return 0;
}