#include <fstream>
#include <iostream>
#include <utility> //pair
#include <string>
#include <cmath> //pow


int main() {

	//std::ifstream inf("Text.txt");	std::cin.rdbuf(inf.rdbuf());

	int Q, N, K;
	std::cin >> Q;

	for (int i = 0; i < Q; i++) {
		std::cin >> N >> K;
		if (K == 1) {
			std::cout << N - 1 << std::endl;
		}
		else {
			int j = 0;
			while (N > 0) {
				N = N - static_cast<int>(std::pow(K, j));
				j++;
			}
			std::cout << j - 1 << std::endl;
		}
	}
}