#include <bits/stdc++.h>
using namespace std;

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

	for (int _ = 0; _ < q; _++)
	{
		int64_t n, k;
		cin >> n >> k;
		
		if (k == 1) {
		    cout << n - 1 << endl;
		    continue;
		}

		int64_t ans = 0;
		for (int64_t tmp = 1; tmp < n; tmp *= k)
		{
			ans++;
		}
		cout << ans << endl;
	}

	return 0;
}