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

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<ld> vld;
typedef pair<ll,ll> Pll;
typedef pair<int,int> Pin;

ll INF = 1e16;
int inf = 1e9;

#define ALL(x) (x).begin(), (x).end()
#define FOR(i, m, n) for (ll i = (m); i < (n); ++i)
#define REVFOR(i, m, n) for (ll i = (n - 1); i >= (m); --i)
#define REP(i, n) FOR(i, 0, n)
#define REVREP(i, n) REVFOR(i, 0, n)
#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define bcnt __builtin_popcountll

#ifdef LOCAL
#include <prettyprint.hpp>
#define debug(...)  cerr << "[" << #__VA_ARGS__ << "]: ", d_err(__VA_ARGS__);
#else
#define debug(...) 83;
#endif

void d_err() {
    cerr << endl;
}

template <typename H, typename... T>
void d_err(H h, T... t) {
    cerr << h << " ";
    d_err(t...);
}

template <typename T>
void print(T x) {
    cout << x << "\n";
}

template <typename T>
void print(vector<T>& x) {
    int N = x.size();
    REP(i, N) {
        if (i > 0) cout << " ";
        cout << x[i];
    }
    cout << "\n";
}

void solve() {
    ll n, a, w, k;
    cin >> n >> a >> w >> k;

    if (n - w > k && a < k) {
        print(":(");
        return;
    }

    if (a < k) {
        // k-th score must be negative
        a -= w;
        if (a >= -1) {
            print(-1);
        } else {
            a = abs(a + 1);
            print(-1 * a / k);
        }

    } else {
        // k-th score can be positive
        if (k < n) {
            print((a - k + 1) / k);
        } else {
            a -= w;
            if (a >= k) {
                print((a - k + 1) / k);
            } else {
                if (a >= -1) {
                    print(-1);
                } else {
                    a = abs(a + 1);
                    print(-1 * a / n);
                }
            }
        }

    }
}

int main(){
    cin.tie(0);
    ios_base::sync_with_stdio(false);
    cout << fixed << setprecision(20);

    int t; cin >> t;
    while(t--) solve();
    
}