You are given two integers l and r, l≤ r. Find the largest possible value of a mod b over all pairs (a, b) of integers for which r≥ a ≥ b ≥ l.

As a reminder, a mod b is a remainder we get when dividing a by b. For example, 26 mod 8 = 2.

Input

Each test contains multiple test cases.

The first line contains one positive integer t (1≤ t≤ 10^4), denoting the number of test cases. Description of the test cases follows.

The only line of each test case contains two integers l, r (1≤ l ≤ r ≤ 10^9).

Output

For every test case, output the largest possible value of a mod b over all pairs (a, b) of integers for which r≥ a ≥ b ≥ l.

Example

Input


4
1 1
999999999 1000000000
8 26
1 999999999


Output


0
1
12
499999999

Note

In the first test case, the only allowed pair is (a, b) = (1, 1), for which a mod b = 1 mod 1 = 0.

In the second test case, the optimal choice is pair (a, b) = (1000000000, 999999999), for which a mod b = 1.
import java.util.Arrays;
import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;

public class Main {

  static Scanner s;
  public static void main(String[] args) {
    s = new Scanner(System.in);

    int len = s.nextInt();
    long a = 0;
    long b = 0;
    long c = 0;
    long res = 0;
    long floor = 0;
    long max = 0;
    long min = 0;
    long d = 0;
    long e = 0;
    long f = 0;
    long g = 0;
    long n = 0;
    long m = 0;
    StringBuilder sb = new StringBuilder();
    String str;
    boolean placeFound = true;
    String result = "";
    int ans = Integer.MIN_VALUE;
    while (len--> 0){
      a = s.nextLong();
      b = s.nextLong();
      if(b / 2 < a){
        System.out.println(b%a);
      }else {
        if(b%2 == 0)
          System.out.println(b/2 - 1);
        else
          System.out.println(b/2);
      }

    }

    s.close();
  }

  private static long[] readArray(long a) {
    long[] nums = new long[(int) a];
    for(int i = 0; i < a; i++)
      nums[i]=s.nextLong();
    return nums;
  }

  private static long gcdByEuclidsAlgorithm(long n1, long n2) {
    if (n2 == 0) {
      return n1;
    }
    return gcdByEuclidsAlgorithm(n2, n1 % n2);
  }

}
