#include<bits/stdc++.h>
using namespace std;
#define rep(i,x,y) for(int i=x;i<y;i++)
#define range(a) a.begin(),a.end()
#define print(A,n) rep(i,0,n){cout<<(i ? " ":"")<<A[i];}cout<<endl;
#define pprint(A,m,n) rep(j,0,m){print(A[j],n);}
const long mod=1e9+7;
const int size=1e6;
int main(){
  int Q;cin>>Q;
  long N,K;
  rep(i,0,Q){
    cin>>N>>K;
    if(K==1){ cout<<N-1<<endl; continue; }
    int j=1;long temp=K;
    while(N-1>temp){
      temp*=K;
      j++;
    }cout<<j<<endl;
  }
}