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

typedef long long ll;
typedef pair<int,int> P;

#define p_ary(ary,a,b) do { cout << "["; for (int count = (a);count < (b);++count) cout << ary[count] << ((b)-1 == count ? "" : ", "); cout << "]\n"; } while(0)
#define p_map(map,it) do {cout << "{";for (auto (it) = map.begin();;++(it)) {if ((it) == map.end()) {cout << "}\n";break;}else cout << "" << (it)->first << "=>" << (it)->second << ", ";}}while(0)

int main() {
    int q;
    cin >> q;
    for (int z = 0;z < q;++z) {
        ll n,k;
        cin >> n >> k;
        if (k == 1) {
            cout << n-1 << endl;
        } else {
            ll c = 1;
            for (int i = 0;i < 100;++i) {
                n -= c;
                if (n <= 0) {
                    cout << i << endl;
                    break;
                }
                c *= k;
            }
        }
    }
    return 0;
}