#include <bits/stdc++.h>
#define LLI long long int
#define FOR(v, a, b) for(LLI v = (a); v < (b); ++v)
#define FORE(v, a, b) for(LLI v = (a); v <= (b); ++v)
#define REP(v, n) FOR(v, 0, n)
#define REPE(v, n) FORE(v, 0, n)
#define REV(v, a, b) for(LLI v = (a); v >= (b); --v)
#define ALL(x) (x).begin(), (x).end()
#define RALL(x) (x).rbegin(), (x).rend()
#define ITR(it, c) for(auto it = (c).begin(); it != (c).end(); ++it)
#define RITR(it, c) for(auto it = (c).rbegin(); it != (c).rend(); ++it)
#define EXIST(c,x) ((c).find(x) != (c).end())
#define fst first
#define snd second
#define popcount __builtin_popcount
#define UNIQ(v) (v).erase(unique(ALL(v)), (v).end())
#define bit(i) (1LL<<(i))

#ifdef DEBUG
#include <misc/C++/Debug.cpp>
#else
#define dump(...) ((void)0)
#endif

#define gcd __gcd

using namespace std;
template <class T> constexpr T lcm(T m, T n){return m/gcd(m,n)*n;}

template <typename I> void join(ostream &ost, I s, I t, string d=" "){for(auto i=s; i!=t; ++i){if(i!=s)ost<<d; ost<<*i;}ost<<endl;}
template <typename T> istream& operator>>(istream &is, vector<T> &v){for(auto &a : v) is >> a; return is;}

template <typename T, typename U> bool chmin(T &a, const U &b){return (a>b ? a=b, true : false);}
template <typename T, typename U> bool chmax(T &a, const U &b){return (a<b ? a=b, true : false);}
template <typename T, size_t N, typename U> void fill_array(T (&a)[N], const U &v){fill((U*)a, (U*)(a+N), v);}

struct Init{
  Init(){
    cin.tie(0);
    ios::sync_with_stdio(false);
  }
}init;


vector<int64_t> convert_base_to(int64_t base, int64_t val){
  if(val == 0) return {0};

  vector<int64_t> ret;
  while(val){
    if(val < base){
      ret.push_back(val);
      break;
    }
    ret.push_back(val % base);
    val /= base;
  }
 
  return ret;
}

int64_t convert_base_from(int64_t base, const vector<int64_t> &val){
  int64_t ret = 0;
  for(auto it = val.rbegin(); it != val.rend(); ++it){
    (ret *= base) += *it;
  }

  return ret;
}




int main(){
  int Q;
  while(cin >> Q){
    while(Q--){
      LLI A,B,C; cin >> A >> B >> C;
      LLI ans = 0;

      if(C == 1){
        ans = -1;
      }else{

        auto res = convert_base_to(C, A);
        dump(res);


        reverse(ALL(res));

        for(auto &x : res){
          if(x) ans += 1;
        }

        ans += (res.size()-1);

        if(res.size() >= 2 and res[0] == 1 and res[1] > 0 and res[1] <= C-2) ans -= 1;

        ans *= B;
        dump(ans);
      }


      cout << ans << endl;
    }
  }

  return 0;
}