#include <iostream>
#include <vector>
#include <algorithm>
#include <array>
#include <iterator>
#include <string>
#include <cctype>
#include <cstring>
#include <cstdlib>
#include <cassert>
#include <cmath>
#include <ctime>
#include <iomanip>
#include <numeric>
#include <stack>
#include <queue>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <bitset>
#include <random>
#include <utility>
#include <functional>
using namespace std;
void Main()
{
	int a,b,c;
	cin >> a >> b >> c;
	if(c == 1)
	{
		cout << "-1\n";
		return;
	}
	unordered_map<int,long long> dp;
	auto dfs = [&](auto dfs,int x) -> long long
	{
		if(x == 0)
		{
			return 0;
		}
		if(dp.find(x) != dp.end())
		{
			return dp[x];
		}
		long long res = (long long) (x + c - 2) / (c - 1) * b;
		if(x % c == 0)
		{
			res = min(res,dfs(dfs,x / c) + b);
		}
		else
		{
			res = min(res,dfs(dfs,x / c * c) + b);
		}
		return dp[x] = res;
	};
	cout << dfs(dfs,a) << "\n";
}
int main()
{
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int tt = 1;
	cin >> tt;
	while(tt--) Main();
}