#include<bits/stdc++.h>
using namespace std;

#define REP(i,x,y) for(ll i=x; i<=y; i++)
#define BIT(t) ((long long 1) << t)
#define PER(i,y,x) for(ll i=y; i>=x; i--)
#define SIZE(v) ll(v.size())
#define vll vector<ll>
#define vvll vector<vector<ll>>
#define pll pair<ll,ll>
#define UNIQUE(v) v.erase( unique(v.begin(), v.end()), v.end() );
typedef long long ll;

int main(){
        ll q;
        cin >> q;
        vll ans;
        REP(iii,1,q){
                ll a,b,c;
                cin >> a >> b >> c;
                if(c == 1){
                        ans.push_back(-1);
                        continue;
                }
                vll v;
                ll cnt = 0;
                while(a > 0){
                        if(a < c){
                                cnt++;
                                a = 0;
                        }else if(a <= 2*(c-1)){
                                cnt += 2;
                                a = 0;
                        }else if(a % c == 0){
                                cnt++;
                                a /= c;
                        }else{
                                cnt++;
                                a /= c;
                                a *= c;
                        }
                }
                ans.push_back(cnt * b);

        }
        for(auto x:ans){
                cout << x << endl;
        }
}