#include <bits/stdc++.h>


using namespace std;
typedef long long ll;
#define REP(i,n) for(int i=0; i<int(n); i++)
#define FOR(i,m,n) for(int i=int(m); i<int(n); i++)
#define ALL(obj) (obj).begin(),(obj).end()
#define VI vector<int>
#define VLL vector<long long>
#define VVI vector<vector<int>>
#define VVLL vector<vector<long long>>
#define VC vector<char>
#define VS vector<string>
#define VVC vector<vector<char>>
#define VB vector<bool>
#define VVB vector<vector<bool>>
#define fore(i,a) for(auto &i:a)

typedef pair <int, int> P;
template<class T> bool chmax(T &a, T b) { if (a < b) { a = b; return true; } return false; }
template<class T> bool chmin(T &a, T b) { if (a > b) { a = b; return true; } return false; }
const int  INF = 1 << 29;
const ll INFL = 1LL << 60;
const ll mod = 1000000007;




int main() {
	
	int q;
	cin >> q;
	REP(_, q) {
		ll a, b, c;
		cin >> a >> b >> c;

		if (c == 1) {
			cout << -1 << endl;
		}
		else {
			VI d;
			if (a < c) {
				cout << b << endl;
			}
			else if (a < c + c) {
				cout << b + b << endl;
			}
			else {
				while (a) {
					d.push_back(a%c);
					a /= c;
				}
				ll ans = b;
				REP(i, d.size() - 1) {
					if (d[i] == 0)ans += b;
					else ans += b + b;
				}


				if (d[d.size() - 1] == 1) {
					ans -= b;
					if (d[d.size() - 2] == 0)ans += b;
				}

				cout << ans << endl;
			}
		}

	}


}