#include <bits/stdc++.h>
#define loop(n) for (int ngtkana_is_genius = 0; ngtkana_is_genius < int(n); ngtkana_is_genius++)
#define rep(i, begin, end) for(int i = int(begin); i < int(end); i++)
#define all(v) v.begin(), v.end()
#define rand(l, r) std::uniform_int_distribution<>(l, r)(mt)
using lint = long long;
auto cmn = [](auto& a, auto b){if (a > b) {a = b; return true;} return false;};
auto cmx = [](auto& a, auto b){if (a < b) {a = b; return true;} return false;};
void debug_impl() { std::cerr << std::endl; }
template <typename Head, typename... Tail>
void debug_impl(Head head, Tail... tail){
  std::cerr << " " << head;
  debug_impl(tail...);
}
#ifndef STOPIT
#define debug(...)\
  std::cerr << std::boolalpha << "[" << #__VA_ARGS__ << "]:";\
  debug_impl(__VA_ARGS__);\
  std::cerr << std::noboolalpha;
#else
#define debug 0;
#endif

int main() {
  std::cin.tie(0); std::cin.sync_with_stdio(false);
  int q; std::cin >> q;
  loop(q) {
    int n, k; std::cin >> n >> k;
    auto ans = 0;
    lint sum = 1;
    lint now = k;
    if (k == 1) {
      std::cout << n - 1 << std::endl;
      continue;
    }
    while(sum < n) {
      sum += now;
      now *= k;
      ans++;
    }
    std::cout << ans << std::endl;
  }
  return 0;
}