// #define _GLIBCXX_DEBUG // for STL debug (optional)
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <string>
#include <cstring>
#include <deque>
#include <list>
#include <queue>
#include <stack>
#include <vector>
#include <utility>
#include <algorithm>
#include <map>
#include <set>
#include <complex>
#include <cmath>
#include <limits>
#include <cfloat>
#include <climits>
#include <ctime>
#include <cassert>
#include <numeric>
#include <fstream>
#include <functional>
#include <bitset>
using namespace std;
using ll = long long int;
using int64 = long long int;
 
template<typename T> void chmax(T &a, T b) {a = max(a, b);}
template<typename T> void chmin(T &a, T b) {a = min(a, b);}
template<typename T> void chadd(T &a, T b) {a = a + b;}
 
int dx[] = {0, 0, 1, -1};
int dy[] = {1, -1, 0, 0};
const int INF = 1LL << 29;
const ll LONGINF = 1LL << 60;
const ll MOD = 1000000007LL;

void solve() {
    ll A, B, C; scanf("%lld%lld%lld", &A, &B, &C);
    if(C == 1) {
        puts("-1");
        return;
    }
    
    map< ll, ll > mp;
    auto calc = [&](auto &&self, ll N) -> ll {
        if(mp.count(N)) return mp[N];
        if(N == 0) return 0;
        
        ll ans = (N+C-2) / (C-1) * B;
        if(N % C == 0) {
            ll k = N / C;
            chmin(ans, self(self, k) + B);
        }
        else {
            // floor
            {
                ll k = N/C;
                if(k!=N) chmin(ans, self(self, k) + 2*B);
            }
            
            // ceil
            {
                ll k = (N+C-1)/C;
                if(k!=N) chmin(ans, self(self, k) + 2*B);
            }
        }
        return mp[N] = ans;
    };
    cout << calc(calc, A) << endl;
}

int main() {
    int Q; scanf("%d", &Q);
    while(Q--) solve();
    return 0;
}