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.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.util.*;

public class Practice {
//	public static long mod = (long) Math.pow(10, 9) + 7;
//	public static long mod2 = 998244353;
//	public static int tt = 1;
//	public static ArrayList<Integer> prime;
//	public static long[] fac = new long[200005];
//	public static long[] invfac = new long[200005];

	public static void main(String[] args) throws Exception {
		PrintWriter pw = new PrintWriter(System.out);
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		int t = Integer.parseInt(br.readLine());
		while (t-- > 0) {
			String[] s1 = br.readLine().split(" ");
			int n = Integer.valueOf(s1[0]);
			int m = Integer.valueOf(s1[1]);
			int x = m / 2 + 1;
			int sec = Math.max(x, n);
			pw.println(m - sec);
		}
		pw.close();
	}

//
//	private static long power(long a, long p) {
//		// TODO Auto-generated method stub
//		long res = 1;
//		while (p > 0) {
//			if (p % 2 == 1) {
//				res = (res * a) % mod;
//			}
//			p = p / 2;
//			a = (a * a) % mod;
//		}
//		return res;
//	}

	// private static int kmp(String str) {
//		// TODO Auto-generated method stub
//		// System.out.println(str);
//		int[] pi = new int[str.length()];
//		pi[0] = 0;
//		for (int i = 1; i < str.length(); i++) {
//			int j = pi[i - 1];
//			while (j > 0 && str.charAt(i) != str.charAt(j)) {
//				j = pi[j - 1];
//			}
//			if (str.charAt(j) == str.charAt(i)) {
//				j++;
//			}
//			pi[i] = j;
//			System.out.print(pi[i]);
//		}
//		System.out.println();
//		return pi[str.length() - 1];
//	}

}

//	private static void getFac(long n, PrintWriter pw) {
//		// TODO Auto-generated method stub
//		int a = 0;
//		while (n % 2 == 0) {
//			a++;
//			n = n / 2;
//		}
//		if (n == 1) {
//			a--;
//		}
//		for (int i = 3; i <= Math.sqrt(n); i += 2) {
//			while (n % i == 0) {
//				n = n / i;
//				a++;
//			}
//		}
//		if (n > 1) {
//			a++;
//		}
//		if (a % 2 == 0) {
//			pw.println("Bob");
//		} else {
//			pw.println("Alice");
//		}
//		//System.out.println(a);
//		return;
//	}

//	private static long power(long a, long p) {
//		// TODO Auto-generated method stub
//		long res = 1;
//		while (p > 0) {
//			if (p % 2 == 1) {
//				res = (res * a) % mod;
//			}
//			p = p / 2;
//			a = (a * a) % mod;
//		}
//		return res;
//	}
//
//	private static void fac() {
//		fac[0] = 1;
//		// TODO Auto-generated method stub
//		for (int i = 1; i < fac.length; i++) {
//			if (i == 1) {
//				fac[i] = 1;
//			} else {
//				fac[i] = i * fac[i - 1];
//			}
//			if (fac[i] > mod) {
//				fac[i] = fac[i] % mod;
//			}
//		}
//	}
//
//	private static int getLower(Long long1, Long[] st) {
//		// TODO Auto-generated method stub
//		int left = 0, right = st.length - 1;
//		int ans = -1;
//		while (left <= right) {
//			int mid = (left + right) / 2;
//			if (st[mid] <= long1) {
//				ans = mid;
//				left = mid + 1;
//			} else {
//				right = mid - 1;
//			}
//		}
//		return ans;
//	}

//private static long getGCD(long l, long m) {
//
//	long t1 = Math.min(l, m);
//	long t2 = Math.max(l, m);
//	if (t1 == 0) {
//		return t2;
//	}
//	while (true) {
//		long temp = t2 % t1;
//		if (temp == 0) {
//			return t1;
//		}
//		t2 = t1;
//		t1 = temp;
//	}
//}