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++) {
    	    int n = sc.nextInt();
    	    long k = sc.nextInt();
    	    int count = 0;
    	    long sum = 0;
    	    long base = 1;
    	    if (k == 1) {
    	        count = n;
    	    } else {
        	    while (sum < n) {
        	        count++;
        	        sum += base;
        	        base *= k;
        	    }
    	    }
    	    sb.append(count - 1).append("\n");
    	}
    	System.out.print(sb);
    }
    
}