#include <bits/stdc++.h>
#define rep(i, a, n) for(int i = a; i < n; i++)
#define int long long
using namespace std;
typedef pair<int, int> P;
const int mod = 1000000007;
const int INF = 1e18;

signed main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int q;
    cin >> q;
    while(q--){
        int n, k;
        cin >> n >> k;
        if(k == 1){
            cout << n - 1 << endl;
            continue;
        }
        int now = 1;
        for(int i = 0;; i++){
            if(n <= now){
                cout << i << endl;
                break;
            }
            now *= k;
        }
    }
}