#include <bits/stdc++.h>
typedef long long ll;
typedef long double ld;
const int INF=1e9,MOD=1e9+7,ohara=1e6+10;
const ll LINF=1e18;
using namespace std;
    
#define rep(i,n) for(ll (i)=0;(i)<(int)(n);(i)++)
#define rrep(i,a,b) for(ll i=(a);i<(b);i++)
#define rrrep(i,a,b) for(ll i=(a);i>=(b);i--)
#define all(v) (v).begin(), (v).end()
#define Size(n) (n).size()
#define Cout(x) cout<<(x)<<endl
#define doublecout(a) cout<<fixed<<setprecision(15)<<a<<endl;
#define Cerr(x) cerr<<(x)<<endl
#define fi first
#define se second
#define P pair<ll,ll> 
#define m_p make_pair
#define V vector<ll> 
#define U_MAP unordered_map<ll,ll>
#define pq priority_queue<ll>
#define rpq priority_queue<ll,vector<ll>,greater<ll>>
#define p_b push_back
    
ll n,cnt,ans,a,b,c,d,tmp,tmpp,m,h,w,x,y,sum,pos,k,q;
ld doua;
int dy[]={1,0,-1,0};
int dx[]={0,1,0,-1};
//int dy[]={-1,0,1,-1,1,-1,0,1};
//int dx[]={-1,-1,-1,0,0,1,1,1};
string alph("abcdefghijklmnopqrstuvwxyz"),s;
bool fl;
struct edge{int to,cost;};
    
//------ Believe yourself as a genius!!!!!! ------
    
int main(void){
    cin.tie(0);
    cout.tie(0);
    ios::sync_with_stdio(false);
    
    cin>>q;
    while(1){
        cin>>a>>b>>c;
        ans=0;
        if(c==1){
            Cout(-1);
        }
        else{
            ll now=a;
            while(1){
                if(now==0)break;
                if(now%c==0){
                    now/=c;
                    ans+=b;
                }
                else{
                    ll cou1=0,cou2=0;
                    ll want=now-now%c;
                    ll cost=(now-want)/(c-1);
                    if((now-want)%(c-1)!=0)cost++;
                    cou1+=b*cost;

                    cost=(now)/(c-1);
                    if((now)%(c-1)!=0)cost++;
                    cou2+=b*cost;

                    if(want-want/c>c-1)ans+=cou1,now=want;
                    else ans+=cou2,now=0;
                }
            }
            Cout(ans);
        }
        q--;
        if(q==0)break;
    }
    return 0;
}