#include <bits/stdc++.h>
#define rep(i, n) for(int i = 0; i < (int)n; i++)
using namespace std;
using ll = long long;
using P = pair<ll, ll>;

int main() {
    int q;
    cin >> q;
    rep(query, q) {
        ll a, b, c;
        cin >> a >> b >> c;
        if(c == 1) {
            cout << -1 << endl;
            continue;
        }
        ll ans = 0;
        while(a > 1) {
            if(a % c) ans++;
            a /= c;
            if(a) ans++;
        }
        cout << ans * b << endl;
    }
    return 0;
}