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

#define REP(i, m, n) for (int i = (m); i < (int)(n); i++)
#define REPS(i, m, n) for (int i = (m); i <= (int)(n); i++)
#define rep(i, n) REP(i, 0, n)
#define reps(i, n) for (int i = 0; i <= (int)(n); i++)
#define rrep(i, x) for (int i = ((int)(x)-1); i >= 0; i--)
#define rreps(i, x) for (int i = (int)(x); i >= 0; i--)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define pb push_back
#define fi first
#define se second
typedef long long ll;
typedef pair<int, int> P;
const int inf = INT_MAX;
const ll INF = 1LL << 60;
const ll mod = 1e9 + 7;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
template<typename A, size_t N, typename T> void Fill(A (&array)[N], const T &val) { fill( (T*)array, (T*)(array+N), val ); }

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    int q; cin >> q;
    rep(_, q) {
        ll n, k; cin >> n >> k;
        if (k == 1 || n == 1) {
            cout << n - 1 << endl;
            continue;
        }
        int cnt = 1;
        ll tmp = k;
        while (tmp + 1 < n) {
            tmp = tmp * k;
            cnt++;
        }
        cout << cnt << endl;
    }
    return 0;
}