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

int main() {
  int q;
  cin >> q;
  while (q--) {
    ll n, k;
    cin >> n >> k;
    if (k == 1) {
      cout << n - 1 << '\n';
    } else {
      ll cur = 1;
      int ans = 0;
      while (cur < n) {
	cur *= k;
	ans++;
      }
      cout << ans << '\n';
    }
  }
  return 0;
}