#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(n);++i)
using namespace std;
typedef long long ll;

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	int q;
	cin >> q;
	vector<ll> n(q);
	vector<ll> k(q);
	rep(i, q) cin >> n[i] >> k[i];
	rep(i, q) {
		int res = 1;
		int ans = 0;
		int sol = n[i];
		while (1) {
			sol = sol - res;
			res *= k[i];
			if (sol > 0) ans++;
			else break;
		}
		cout << ans << endl;
	}
}