#include<iostream>
#include<string>
#include<queue>
#include<algorithm>
#include<map>
#include<set>
#include<vector>
#include<math.h>

using namespace std;

#define INF 1000000007
#define LINF (1LL << 62)

typedef long long i64;
typedef pair<i64,i64> P;


i64 q, n[101], m[101];

int main(){
	cin >> q;
	for(int i = 0; i < q; i++){
		cin >> n[i] >> m[i];
	}
	
	for(int i = 0; i < q; i++){
		if(m[i] == 1){
			cout << n[i] - 1 << endl;
			continue;
		}
		i64 cnt = 0, p = 1;
		for(i64 j = 1; j < n[i]; j+=p){
			cnt++;
			p *= m[i];
		}
		cout << cnt << endl;
	}
	
	return 0;
}