#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define all(A) A.begin(),A.end()
using vll = vector<ll>;
#define rep(i, n) for (long long i = 0; i < (long long)(n); i++)
using Graph = vector<vector<ll>>;
ll mod=1e9+7;

int main() {
    ll Q;
    cin>>Q;
    rep(q,Q){
      ll N,K;
      cin>>N>>K;
      if(K==1)cout<<N-1<<endl;
      else{
        ll k=1;
        ll a=1;
        ll an=0;
        while(a<N){
          k*=K;
          a+=k;
          an++;
        }
        cout<<an<<endl;
      }
    }
}