use std::io::Read;

fn main() {
	let mut s = String::new();
	std::io::stdin().read_to_string(&mut s).ok();
	let v: Vec<i64> =
		s.split_whitespace().skip(1).flat_map(str::parse).collect();
	v.chunks(2).for_each(|x| {
		let (mut n, k) = (x[0], x[1]);
		let mut r = k;
		let mut l = 0;
		while n > 1 {
			l += 1;
			n -= r;
			r *= k;
		}
		println!("{}", l)
	});
}