#include <bits/stdc++.h>
#pragma GCC diagnostic ignored "-Wsign-compare"
#pragma GCC diagnostic ignored "-Wsign-conversion"

#define NDEBUG
using i32 = int32_t;
using i64 = int64_t;
using u32 = uint32_t;
using u64 = uint64_t;
using uint = unsigned int;
using usize = std::size_t;
using ll = long long;
using ull = unsigned long long;
using ld = long double;
template<typename T> constexpr T popcount(const T u) { return u ? static_cast<T>(__builtin_popcountll(static_cast<u64>(u))) : static_cast<T>(0); }
template<typename T> constexpr T log2p1(const T u) { return u ? static_cast<T>(64 - __builtin_clzll(static_cast<u64>(u))) : static_cast<T>(0); }
template<typename T> constexpr T msbp1(const T u) { return log2p1(u); }
template<typename T> constexpr T lsbp1(const T u) { return __builtin_ffsll(u); }
template<typename T> constexpr T clog(const T u) { return u ? log2p1(u - 1) : static_cast<T>(u); }
template<typename T> constexpr bool ispow2(const T u) { return u and (static_cast<u64>(u) & static_cast<u64>(u - 1)) == 0; }
template<typename T> constexpr T ceil2(const T u) { return static_cast<T>(1) << clog(u); }
template<typename T> constexpr T floor2(const T u) { return u == 0 ? static_cast<T>(0) : static_cast<T>(1) << (log2p1(u) - 1); }
template<typename T> constexpr bool btest(const T mask, const usize ind) { return ((static_cast<u64>(mask) >> ind) & static_cast<u64>(1)); }
template<typename T> constexpr T bcut(const T mask, const usize ind) { return ind == 0 ? static_cast<T>(0) : static_cast<T>((static_cast<u64>(mask) << (64 - ind)) >> (64 - ind)); }
template<typename T> bool chmin(T& a, const T& b) { return (a > b ? a = b, true : false); }
template<typename T> bool chmax(T& a, const T& b) { return (a < b ? a = b, true : false); }
constexpr unsigned int mod                  = 1000000007;
template<typename T> constexpr T inf_v      = std::numeric_limits<T>::max() / 4;
template<typename Real> constexpr Real pi_v = Real{3.141592653589793238462643383279502884};
template<typename T>
T read()
{
    T v;
    return std::cin >> v, v;
}
template<typename T>
std::vector<T> read_vec(const std::size_t size)
{
    std::vector<T> v(size);
    for (auto& e : v) { std::cin >> e; }
    return v;
}
template<typename... Types>
auto read_vals() { return std::tuple<std::decay_t<Types>...>{read<Types>()...}; }
#define SHOW(...) static_cast<void>(0)
template<typename T>
std::vector<T> make_v(const std::size_t size, T v) { return std::vector<T>(size, v); }
template<class... Args>
auto make_v(const std::size_t size, Args... args) { return std::vector<decltype(make_v(args...))>(size, make_v(args...)); }
int main()
{
    const auto q = read<usize>();
    for (usize i = 0; i < q; i++) {
        const auto [a, b, c] = read_vals<ll, ll, ll>();
        if (c == 1) {
            std::cout << -1 << std::endl;
            continue;
        }
        usize s = 0, cnt = 0;
        for (usize i = 0, k = a; k > 0; i++, k /= c) {
            if (k % c != 0) { cnt++, chmax(s, i); }
        }
        ll ans = (ll)(s + cnt) * b;

        ll base = 1;
        for (; base <= a; base *= c) {}
        if (base >= c * c) {
            base /= (c * c);
            const ll u = a / base;
            if (c < u and u <= 2 * c - 2) { ans -= b; }
        }
        std::cout << ans << std::endl;
    }
    return 0;
}