#include<bits/stdc++.h>
#define x first
#define y second
#define eb emplace_back
#define pb push_back
#define FOR(i,a,b) for(int i=(a);i<=(b);++i)
#define ROF(i,a,b) for(int i=(a);i>=(b);--i)
#define all(x) (x).begin(),(x).end()
#define mp make_pair
#define sz(x) (int)(x).size()
#define make_unique(x) sort(all(x)), (x).erase(unique(all(x)), (x).end())

using namespace std;

typedef long long i64;
//typedef __int128 i128;
typedef long double ld;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<i64> vl;
typedef vector<vl> vvl;
typedef pair<int,int> pii;
typedef pair<i64,i64> pll;
typedef tuple<int,int,int> iii;
typedef vector<pii> vpii;
typedef vector<pll> vpll;

int readInt() { int a; scanf("%d",&a); return a; }
i64 readLong() { i64 a; scanf("%lld",&a); return a; }
char readChar() { char a; scanf(" %c",&a); return a; }
double readDouble() { double a; scanf(" %lf",&a); return a; }
void readString(char *s) { scanf(" %s",s); }

const int mod = 998244353;
int add(int a, int b) { return ((a+=b)>=mod) ? a-mod:a; }
int mul(int a, int b) { return a*1ll*b%mod; }
int pw(int a, int b) {
	int ans = 1, res = a;
	for(int i = 1; i <= b; i*=2, res=mul(res,res)) {
		if(i&b) {
			ans = mul(ans, res);
		}
	}
	return ans;
}

typedef long long ll;

void solve() {
	ll n, d;
	scanf(" %lld %lld",&n,&d);
	ll val = 1;
	FOR(i,1,60) {
		if (val <= n/(d+1)) {
			val *= (d+1);
		} else {
			printf("%d\n",i);
			return ;
		}
		if(val == n) {
			printf("%d\n",i);
			return ;
		}
	}
}

int main() {
	int t= readInt();
	while(t--) {
		solve();
	}
	return 0;
}