import java.util.*;

class Main3{
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		int q = sc.nextInt();
		long[] n = new long[q];
		long[] k = new long[q];
		for(int i = 0; i < q; i++){
			n[i] = sc.nextLong();
			k[i] = sc.nextLong();
		}
		for(int i = 0; i < q; i++){
			if(k[i] == 1){
				System.out.println(n[i]-1);
			}else{
				int cou = 1;
				long tmp = k[i];
				while(tmp < n[i]){
					tmp*=k[i];
					cou++;
				}
				System.out.println(cou);
			}
		}
	}
}