#include<bits/stdc++.h>
using namespace std;
typedef long long ll;

int main(){
  int Q; cin >> Q;
  for(int i = 0; i < Q; i++){
    ll n,k; cin >> n >> k;
    ll res= n*(k-1)+1;
    ll m = 0;
    if( k == 1){ cout << n-1 << endl; continue;}
    while( res/k >= k){ res/= k; m++;}
    
    cout << m+1 << endl;
  }
  
  return 0;}