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

int main() {
	int64_t N, K, Q;
	cin >> Q;

	for (int i = 0; i < Q; i++) {
		cin >> N >> K;
		if (N - 1 < K) {
			cout << 1 << endl;
			continue;
		}
		if (K == 1) {
			cout << N - 1 << endl;
			continue;
		}

		int c = 0;
		N--;
		int64_t s = 0;
		int64_t k = K;
		while (1) {
			s += K;
			//cout << "s;" << s << endl;
			//cout << "N-s;" << N-s << endl;
			if (N - s == 0) {
				c++;
				break;
			}
			else {
				c++;
				k *= K;
				//cout << "K:" << K << endl;
				if ((N-s > 0) && (N-s < k)) {
					c++;
					break;
				}
			}
		}

		cout << c << endl;
	}
}