#include "bits/stdc++.h"

using namespace std;

//------------------------------- Libraries --------------------------------//

//------------------------------- Type Names -------------------------------//

using i64 = int_fast64_t;

using seika = string;
template <class kizuna>
using akari = vector<kizuna>;
template <class yuzuki>
using yukari = akari<akari<yuzuki>>;
template <class tsurumaki>
using maki = akari<yukari<tsurumaki>>;
template <class kotonoha>
using akane = priority_queue<kotonoha, akari<kotonoha>, greater<kotonoha>>;
template <class kotonoha>
using aoi = priority_queue<kotonoha>;

//------------------------------- Dubug Functions ---------------------------//
inline void print()
{
    cout << endl;
}
template <typename First, typename... Rest>
void print(const First &first, const Rest &... rest)
{
    cout << first << ' ';
    print(rest...);
}
//------------------------------- Solver ------------------------------------//

void solve()
{
    int n, k, q;
    cin >> q;
    while (q--)
    {
        cin >> n >> k;
        if (k == 1)
        {
            cout << n - 1 << endl;
        }
        else
        {
            cout << (int)ceil(1. * log(n) / log(k)) << endl;
        }
    }
}

int main()
{
    solve();
    return 0;
}