#pragma GCC optimize ("O3")
#pragma GCC target ("avx")
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i, n) for(int i = 0; i < (n); i++)
#define rep1(i, n) for(int i = 1; i <= (n); i++)
#define co(x) cout << (x) << "\n"
#define cosp(x) cout << (x) << " "
#define ce(x) cerr << (x) << "\n"
#define cesp(x) cerr << (x) << " "
#define pb push_back
#define mp make_pair
#define chmin(x, y) x = min(x, y)
#define chmax(x, y) x = max(x, y)
#define Would
#define you
#define please

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


	int Q;
	cin >> Q;
	rep(i, Q) {
		int A, B, C;
		cin >> A >> B >> C;

		if (C == 1) co(-1);
		else {
			ll kotae = 0;
			while (A) {
				if (A < C) {
					kotae++;
					A = 0;
				}
				else if (A - C + 1 < C) {
					A -= C - 1;
					kotae++;
				}
				else if (A % C) {
					A -= A % C;
					kotae++;
				}
				else {
					A /= C;
					kotae++;
				}
			}
			co(kotae * B);
		}
	}


	Would you please return 0;
}