#include <iostream>
#include <vector>
#include <algorithm>
#include <set>
#include <numeric>
#include <math.h>
#include <map>
using namespace std;
typedef long long int ll;

int main(){
	cin.tie(nullptr);
	ios::sync_with_stdio(false);
	int q; cin >> q;
    while(q--){
        ll n,k; cin >> n >> k;
        if(k==1){
            cout << n-1 << endl;
            continue;
        }
        ll res=0;
        ll sum=0;
        ll d=k;
        while(sum<n){
            res++;
            sum+=d;
            d*=k;
        }
        cout << res << endl;
    }
}