#include <bits/stdc++.h>
typedef long long ll;
using namespace std;
#define all(x) (x).begin(), (x).end()
#define MOD 1000000007
int main() {
    int q;
    cin >> q;
    while(q--) {
        ll n, k;
        cin >> n >> k;
        if(k == 1) {
            cout << n - 1 << endl;
        } else {
            ll mul = 1, cum = 1;
            ll ans = 0;
            while(cum < n) {
                mul *= k;
                cum += mul;
                ans++;
            }
            cout << ans << endl;
        }
    }
}