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

int main() {
  int N;
  cin >> N;
  for (int i = 0, n, k; i < N && cin >> n >> k; i++) {
    if (k == 1) {
      cout << n - 1 << "\n";
      continue;
    }
    long tmp = 1, ans = 0;
    while (n > tmp && ++ans) tmp += pow(k, ans);
    cout << ans << "\n";
  }
}