#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;

#define pb push_back

const ld pi = 3.14159265358979323846;
// const int mod = 998244353;
const ll INF = 1e18;

template<typename T>
T chmax(T a, T b) {
    return a > b ? a : b;
}

template<typename T>
T chmin(T a, T b) {
    return a > b ? b : a;
}

const int N = (int)2e5 + 1, M = N * 2;

using lll = __int128;

ostream &operator<<(std::ostream &os, lll n) {
    std::string s;
    while (n) {
        s += '0' + n % 10;
        n /= 10;
    }
    std::reverse(s.begin(), s.end());
    return os << s;
}


ll ceil_div(ll n, ll m) {
    if(n >= 0){
        return (n + m - 1) / m;
    } 
    else{
        return n / m;
    }
}
 
ll floor_div(ll n, ll m) {
    if (n >= 0){
        return n / m;
    } 
    else{
        return (n - m + 1) / m;
    }
}

template<class T>
void chmax(T &a, T b) {
    if(a < b) {
        a = b;
    }
}

lll gcd(lll a, lll b) {
    return b ? gcd(b, a % b) : a;
}

void solve(){
    ll n, d;
    cin >> n >> d;

    d = (lll)d + 1;
    lll qwq =  1;

    for(int i = 1; i <= 64; i++){
        qwq = qwq * d;
        if(qwq >= n){
            cout << i << endl;
            return;
        }
    }
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);

    int t = 1;
    cin >> t;

    while(t--){
        solve();
    }

    return 0;
}