#include <iostream>
#include <array>
#include <algorithm>
#include <vector>
#include <set>
#include <unordered_set>
#include <cmath>
#include <complex>
#include <deque>
#include <iterator>
#include <numeric>
#include <map>
#include <unordered_map>
#include <queue>
#include <stack>
#include <string>
#include <tuple>
#include <utility>
#include <limits>
#include <iomanip>
using namespace std;

using ll=long long;
template<class T> using V = vector<T>;
template<class T, class U> using P = pair<T, U>;
using vll = V<ll>;
using vvll = V<vll>;
#define rep(i, k, n) for (ll i=k; i<(ll)n; ++i)
#define REP(i, n) rep(i, 0, n)
#define ALL(v) v.begin(),v.end()
template<class T> inline bool chmax(T& a, T b) {if (a<b) {a=b; return true;} return false;}
template<class T> inline bool chmin(T& a, T b) {if (a>b) {a=b; return true;} return false;}

const ll MOD = 1000000007;
const ll HIGHINF = (ll)1e18;

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    ll q; cin >> q;
    while (q-->0) {
        ll a, b, c; cin >> a >> b >> c;
        if (c==1) cout << "-1\n";
        else {
            ll tmpa = a;
            vll bit;
            while (tmpa>0) {
                bit.push_back(tmpa%c);
                tmpa /= c;
            }
            reverse(ALL(bit));

            ll m = bit.size();
            vll sum(m+1, 0), powC(m, 1), dp(m+1, a);
            rep(i, 1, m) powC[i] = powC[i-1]*c;
            rep(i, 1, m+1) REP(j, i) sum[i] += bit[j]*powC[i-j-1];

            dp[0] = 0;
            REP(i, m) {
                if (sum[i]*c == sum[i+1]) chmin(dp[i+1], dp[i]+1);
                if (sum[i]+c-1 >= sum[i+1]) chmin(dp[i+1], dp[i]+1);
                if (sum[i]*c+c-1 >= sum[i+1]) chmin(dp[i+1], dp[i]+2);
                if (i+2<=m && sum[i]+2*c-2 >= sum[i+2]) chmin(dp[i+2], dp[i]+2);
            }
            cout << dp[m]*b << '\n';
        }
    }
    return 0;
}