#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<int,int>;
#define rep(i,n) for(int i=0;i<n;i++)

const ll mod = ll(1e9) + 7;
const int INF = 1<<29;

int main(){
    int q;
    cin >> q;
    rep(i,q){
        int n,k;
        cin >> n >> k;
        if (k==1){
            cout << n-1 << endl;
            continue;
        }
        int ans = 0;
        while (n>=0){
            ans++;
            n -= pow(k,ans);
        }
        cout << ans << endl;
    }
    return 0;
}