#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<vector>
#include<cmath>
#include<algorithm>
#include<map>
#include<queue>
#include<deque>
#include<iomanip>
#include<tuple>
using namespace std;
typedef long long int LL;
typedef pair<int,int> P;
typedef pair<LL,int> LP;
const int INF=1<<30;
const LL MAX=1e9+7;

void array_show(int *array,int array_n,char middle=' '){
	for(int i=0;i<array_n;i++)printf("%d%c",array[i],(i!=array_n-1?middle:'\n'));
}
void array_show(LL *array,int array_n,char middle=' '){
	for(int i=0;i<array_n;i++)printf("%lld%c",array[i],(i!=array_n-1?middle:'\n'));
}

int main(){
	LL n,m,t;
	LL i,j,k;
	LL a,b,c;
	cin>>t;
	while(t--){
		cin>>n>>m;
		if(m==1){
			cout<<n-1<<endl;
			continue;
		}
		a=1,b=0,c=1;
		while(a<n){
			c*=m,a+=c,b++;
		}
		cout<<b<<endl;
	}
}