#include <iostream>
#include <vector>
using namespace std;

int main() {
  int Q;
  cin >> Q;
  vector<int> N(Q), K(Q);
  for (int i = 0; i < Q; ++i)
    cin >> N[i] >> K[i];
  for (int i = 0; i < Q; ++i) {
    int ans = 0, v = 1, p = 1;
    while (v < N[i])
      ++ans, p *= K[i], v += p;
    cout << ans << endl;
  }
}