#include "bits/stdc++.h"
#define in std::cin
#define out std::cout
#define rep(i,N) for(LL i=0;i<N;++i)
typedef long long int LL;

int main()
{
	LL Q;
	in >> Q;
	std::vector<LL>A(Q), B(Q), C(Q);
	rep(i, Q) in >> A[i] >> B[i] >> C[i];

	rep(i, Q)
	{
		if (C[i] == 1) out << -1 << std::endl;
		else
		{
			LL cnt = 0, t = A[i], ans = 1145148101919;
			while (t > 0)
			{
				if (t % C[i] == 0)
				{
					t /= C[i];
					++cnt;
				}
				else
				{
					ans = std::min(ans, cnt + (t + C[i] - 2) / (C[i] - 1));
					t -= t % C[i];
					++cnt;
				}
			}
			ans = std::min(ans, cnt);

			out << ans * B[i] << std::endl;
		}
	}
}