#include <bits/stdc++.h>
using namespace std;

#define int long long

signed main(){
    int q;
    cin >> q;
    while(q--){
        int n, k;
        cin >> n >> k;

        int ans = 0;
        int now = k;
        int num = 1;
        if(k == 1){
            cout << n-1 << endl;
            continue;
        }
        while(num < n){
            num += now;
            ans++;
            now *= k;
        }

        cout << ans << endl;
    }

    return 0;
}