#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <cstring>
#include <cstdlib>
#include <cmath>
using namespace std;
using ll = long long;

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

    for (int h = 0; h < q; h++) {
        int n, k;
        cin >> n >> k;

        if (k == 1) {
            cout << n - 1 << endl;
            continue;
        }
        ll s = 1, c = 1;
        for (int i = 0;; i++) {
            if (s >= n) {
                cout << i << endl;
                break;
            }
            c *= k;
            s += c;
        }
    }

    return 0;
}