import java.util.*;

public class Main {
 	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int q = sc.nextInt();
		StringBuilder sb = new StringBuilder();
		for (int i = 0; i < q; i++) {
		    sb.append(getCount(sc.nextInt(), sc.nextInt())).append("\n");
		}
		System.out.println(sb);
   }
   
   static int getCount(long n, int k) {
       int idx = 0;
       while (n > 0) {
           n -= (long)(Math.pow(k, idx));
           idx++;
       }
       return idx - 1;
   }
}