#include "bits/stdc++.h"
using namespace std;
#define Rep(i,n) for(int i=0;i<(int)(n);i++)
#define For(i,n1,n2) for(int i=(int)(n1);i<(int)(n2);i++)
#define REP(i,n) for(ll i=0;i<(ll)(n);i++)
#define RREP(i,n) for(ll i=((ll)(n)-1);i>=0;i--)
#define FOR(i,n1,n2) for(ll i=(ll)(n1);i<(ll)(n2);i++)
#define RFOR(i,n1,n2) for(ll i=((ll)(n1)-1);i>=(ll)(n2);i--)
#define all(a)  (a).begin(),(a).end()
#define SORT(a) sort((a).begin(),(a).end())
#define oorret 0
#define oor(x) [&](){try{x;} catch(const out_of_range& oor){return oorret;} return x;}()
#define IOS cin.tie(0),ios::sync_with_stdio(false)
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll, ll> P;
template<typename T1, typename T2> inline bool chmin(T1& a, T2 b) { if (a > b) { a = b; return 1; }return 0; }
template<typename T1, typename T2> inline bool chmax(T1& a, T2 b) { if (a < b) { a = b; return 1; }return 0; }
template<class Type>struct is_vector : std::false_type {};
template<class ValueType, class Alloc>struct is_vector<std::vector<ValueType, Alloc>> : std::true_type {};
template <typename T> inline ostream& operator << (ostream& out, const vector<T>& v) {
	if (v.empty())return out;
	constexpr bool is_vector_v = is_vector<T>::value;
	if (is_vector_v)for (auto itr = v.begin(); itr != v.end();)out << (*itr), out << ((++itr != v.end()) ? "\n" : "");
	else for (auto itr = v.begin(); itr != v.end();)out << (*itr), out << ((++itr != v.end()) ? " " : "");
	return out;
}
inline void put() {}
template<class T> inline void put(const T& first) { std::cout << first << "\n"; }
template<class T, class... N> inline void put(const T& first, const N& ... rest) { std::cout << first << " "; put(rest...); }
inline void putn() {}
template<class T, class... N> inline void putn(const T& first, const N& ... rest) { std::cout << first << "\n"; putn(rest...); }

int main() {
	IOS;
	int t;
	cin >> t;
	REP(i, t) {
		ll a, b, c;
		cin >> a >> b >> c;
		if (c == 1) {
			put(-1);
			continue;
		}
		if (c >= a) {
			put(1);
			continue;
		}
		queue<P> q;
		q.push(P(a, 0));
		set<int> st;
		while (true) {
			auto p = q.front();
			q.pop();
			if (p.first < c) {
				put(p.second + b);
				break;
			}
			int m = p.first % c;
			if (m == 0) {
				int nc = p.first / c;
				auto itr = st.find(nc);
				if (itr == st.end()) {
					q.push(P(p.first / c, p.second + b));
				}
				
			} else {
				int nc = p.first - m;
				auto itr = st.find(nc);
				if (itr == st.end()) {
					q.push(P(p.first - m, p.second + b));
				}
				nc = p.first - c + 1;
				auto itr2 = st.find(nc);
				if (itr2 == st.end()) {
					q.push(P(p.first - c + 1, p.second + b));
				}
			}
		}
	}
	return 0;
}