#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <iomanip>
#include <cmath>
#include <map>
using namespace std;
#define REP(i,n) for (int i=0;i<(n);++i)
using ll = long long;

ll q, n, k;

int main() {
  cin.tie(0); ios_base::sync_with_stdio(false); 
  cin >> q;
  REP(i, q) {
    cin >> n >> k;
    if(k == 1) cout << n-1;
    else {
      ll ans = 0, h = 1;
      while(h < n) {
        h *= k;
        ++ans;
      }
      cout << ans << '\n';
    }
  }
  return 0;
}