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

int main() {
  int query;
  cin >> query;
  for (int i = 0; i < query; i++) {
    int n, k;
    cin >> n >> k;
    if (k == 1) {
      cout << n - 1 << endl;
      continue;
    }
    else {
      int64_t now = 1, sum = 1;
      int ans = 0;
      while (true) {
        now *= k;
        sum += now;
        ans ++;
        if (sum >= n) break;
      }
      cout << ans << '\n';
    }
  }
  return 0;
}