#include <bits/stdc++.h>

using namespace std;

using ll = long long;
using ull = unsigned long long;
using ld = long double;
using P = pair<ll, ll>;
using tp = tuple<ll, ll, ll>;

template <class T>
using vec = vector<T>;
template <class T>
using vvec = vector<vec<T>>;

#define all(hoge) (hoge).begin(), (hoge).end()
#define en '\n'
#define rep(i, m, n) for(ll i = (ll)(m); i < (ll)(n); ++i)
#define rep2(i, m, n) for(ll i = (ll)(n)-1; i >= (ll)(m); --i)
#define REP(i, n) rep(i, 0, n)
#define REP2(i, n) rep2(i, 0, n)

constexpr long long INF = 1LL << 60;
constexpr int INF_INT = 1 << 25;
constexpr long long MOD = (ll)1e9 + 7;
//constexpr long long MOD = 998244353LL;
static const ld pi = 3.141592653589793L;

#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")

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

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

//グラフ関連
struct Edge {
    int to, rev;
    ll cap;
    Edge(int _to, ll _cap, int _rev) : to(_to), cap(_cap), rev(_rev) {}
};

typedef vector<Edge> Edges;
typedef vector<Edges> Graph;

void add_edge(Graph &G, int from, int to, ll cap, bool revFlag, ll revCap) {
    G[from].push_back(Edge(to, cap, (int)G[to].size()));
    if(revFlag)
        G[to].push_back(Edge(from, revCap, (int)G[from].size() - 1));
}

void solve() {
    ll n, a, w, k;
    cin >> n >> a >> w >> k;
    if(k == 1) {
        cout << a << en;
    } else if(k < n) {
        ll now = a / k;
        if(a % k != k - 1) {
            if(now == 0 and w == 0) {
                cout << ":(" << en;
                return;
            }
            now--;
        }
        cout << now << en;
    } else {
        if(a == w) {
            cout << -2 << en;
        } else if(a + 1 == w) {
            cout << -1 << en;
        } else if(a < w) {
            ll d = w - a;
            ll now = -(d / n);
            if(d % n != 1)
                now--;
            cout << now << en;
        } else {
            ll d = a - w;
            ll now = d / n;
            if(d % n != n - 1)
                now--;
            cout << now << en;
        }
    }
}

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

    ll t;
    cin >> t;
    REP(i, t - 1) {
        solve();
    }

    solve();

    return 0;
}