#include <iostream>
using namespace std;
using ll = long long;
ll q, a, b, c;

int main() {
  cin.tie(0); ios_base::sync_with_stdio(false);
  cin >> q;
  while(q--) {
    cin >> a >> b >> c;
    if(c == 1) {
      cout << -1 << '\n';
      continue;
    }
    ll ans = b;
    a -= a % c;
    while(a) {
      while(a % c == 0) a /= c, ans += b;
      if(a <= (c-1)*2) ans += (a + c - 2) / (c - 1) * b, a = 0;
      else if(a % c) a -= a % c, ans += b;
    }
    cout << ans << '\n';
  }
  return 0;
}