#include <iostream>
#include <vector>
#include <deque>


int main() {

  int Q;
  std::cin >> Q;
  for (int i = 0; i < Q; ++i) {
    int N, K;
    std::cin >> N >> K;
    if (K == 1) {
      std::cout << N - 1 << std::endl;
    } else {
      int depth = 0;
      long long res = N - 1;
      long long p = 1;
      while (res > 0) {
	++depth;
	p *= K;
	res -= p;
      }
      std::cout << depth << std::endl;
    }
  }
}