#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <functional>
#include <algorithm>
#include <string>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <stack>
using namespace std;
template<class T, class Compare = less<T> >
using MaxHeap = priority_queue<T, vector<T>, Compare>;
template<class T, class Compare = greater<T> >
using MinHeap = priority_queue<T, vector<T>, Compare>;
using llong = long long;

llong tmpn, tmpk;
__int128_t n, k;

int main() {
    llong q;
    cin >> q;

    while (q--) {
        cin >> tmpn >> tmpk;
        n = tmpn;
        k = tmpk;

        __int128_t d = 1;
        __int128_t x = 1;
        llong cnt = 0;
        while (x < n) {
            x += d;
            d *= k;
            cnt++;
        }

        cout << cnt << endl;
    }

    return 0;
}