#include<iostream>
#include<fstream>
#include <cmath>
#include <algorithm>
#include <stack>
#include <vector>
#include <random>
#include <unordered_set>
using namespace std;
typedef long long ll;
#define FOR(I,A,B) for(int I = int(A); I < int(B); ++I)

int main(){
    ll n;
    cin >> n;
    while(n--){
        ll a,b;
        cin >> a >> b;
        ll ans=0,c=1;
        if(b==1){
            cout << a-1 << endl;
            continue;
        }
        while(c<a){
            c *= b;
            ans++;
        }
        cout << ans << endl;
    }
}