#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<long long,long long> pll;
#define pb push_back
#define mp make_pair
#define rep(i,n) for(int i=0;i<(n);++i)
constexpr int mod=1000000007;
constexpr int mod1=998244353;
vector<int> dx={0,1,0,-1},dy={-1,0,1,0};
bool inside(int y,int x,int h,int w){
	if(y<h && y>=0 && x<w && x>=0) return true;
	return false;
}





int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);
	int q;cin >> q;
	rep(i,q){
		ll n,k;cin >> n >> k;
		if(k == 1){
			cout << n - 1 << endl;
			continue;
		}
		ll ans = 0, t = 1, m = k;
		rep(j,40){
			if(n < t) break;
			t += m;
			m *= k;
			ans++;
		}
		cout << ans << endl;
	}
}