#include <bits/stdc++.h>
#define pb push_back
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
#define mp make_pair
#define f first
#define s second
#define int long long
using namespace std;
using ll = long long;
using pii = pair <int, int>;
const int N = 1e5 + 2, inf = 1e9;


long long n, d;

main() {
	ios :: sync_with_stdio(0);
	cin.tie(0), cout.tie(0);
	int t;
	cin >> t;
	while(t--){
		cin >> n >> d;
		if(n == 1){
			cout << "0\n";
			continue;
		}
		if(n == 2){
			cout << "1\n";
			continue;
		}
		if(d >= n - 1){
			cout << "1\n";
			continue;
		}
		n--;                  
		
		int x = 0;
		int res = 1;
		while(res <= n){
			x++;
			res *= (d + 1);
		}
		
		cout << x << "\n";
	}
	return 0;
}