#include<bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i,n) for(ll i=0;i<(n);++i)

main(){

  ll q;
  cin>>q;
  vector<ll> n(q),k(q);
  rep(i,q)cin>>n[i]>>k[i];

  auto solve = [](ll n,ll k){
    if(k==1)return n-1;
    n--;
    ll cnt=0,leaf=1;
    while(leaf<n){
      cnt++;
      leaf*=k;
    }
    return cnt;
  };

  rep(i,q){
    cout<<(solve(n[i],k[i]))<<endl;
  }
}