You are playing another computer game, and now you have to slay n monsters. These monsters are standing in a circle, numbered clockwise from 1 to n. Initially, the i-th monster has a_i health.

You may shoot the monsters to kill them. Each shot requires exactly one bullet and decreases the health of the targeted monster by 1 (deals 1 damage to it). Furthermore, when the health of some monster i becomes 0 or less than 0, it dies and explodes, dealing b_i damage to the next monster (monster i + 1, if i < n, or monster 1, if i = n). If the next monster is already dead, then nothing happens. If the explosion kills the next monster, it explodes too, damaging the monster after it and possibly triggering another explosion, and so on.

You have to calculate the minimum number of bullets you have to fire to kill all n monsters in the circle.

Input

The first line contains one integer T (1 ≤ T ≤ 150000) — the number of test cases.

Then the test cases follow, each test case begins with a line containing one integer n (2 ≤ n ≤ 300000) — the number of monsters. Then n lines follow, each containing two integers a_i and b_i (1 ≤ a_i, b_i ≤ 10^{12}) — the parameters of the i-th monster in the circle.

It is guaranteed that the total number of monsters in all test cases does not exceed 300000.

Output

For each test case, print one integer — the minimum number of bullets you have to fire to kill all of the monsters.

Example

Input


1
3
7 15
2 14
5 3


Output


6
import java.util.*;
import java.io.*;
import java.math.*;

public class Main {

	//static int p = 1000000007;
	static int p = 998244353;
	
	

	public static void main(String args[]) throws IOException {
		Scanner sc = new Scanner();
		PrintWriter out = new PrintWriter(System.out);
		//Mod mod = new Mod();
		//mod.precalc();

		int t = 1;
		t = sc.nextInt();

		
		while (t-- > 0) {
			
			int n=sc.nextInt();
			long a[]=new long[n], b[]=new long[n], ans=0, min=Long.MAX_VALUE;
			for(int i=0; i<n; i++) {
				a[i]=sc.nextLong();
				b[i]=sc.nextLong();
				min = min<=a[i]?(min<=b[i]?min:b[i]):a[i]<=b[i]?a[i]:b[i];
			}
			 if(n==1) {
				 out.println(a[0]);
				 continue;
			 }
			 
			 for(int i=1; i<n; i++)
				 if(a[i]>b[i-1])
					 ans+=a[i]-b[i-1];
			 if(a[0]>b[n-1])
				 ans+=a[0]-b[n-1];
			 out.println(ans+min);
		}
		out.flush();
	}
	
	
	
    
	static int count(int x, int[] arr) {
		int count = 0;

		for (int i = 0; i < arr.length; i++)
			if (arr[i] == x)
				count++;
		return count;
	}

	public static String reverseString(String str) {
		StringBuilder sb = new StringBuilder(str);
		sb.reverse();
		return sb.toString();
	}

	static boolean isPalindrome(String str) {
		int i = 0, j = str.length() - 1;

		while (i < j) {

			if (str.charAt(i) != str.charAt(j))
				return false;

			i++;
			j--;
		}
		return true;
	}

	static void print(int[] arr) {
		for (int i = 0; i < arr.length; i++)
			System.out.print(arr[i] + " ");
		System.out.println();
	}

	public static int abs(int x) {
		return ((x > 0) ? x : -x);
	}

	public static long abs(long x) {
		return ((x > 0) ? x : -x);
	}

	public static int max(int a, int b) {
		return Math.max(a, b);
	}

	public static long max(long a, long b) {
		return Math.max(a, b);
	}

	public static int min(int a, int b) {
		return Math.min(a, b);
	}

	public static long min(long a, long b) {
		return Math.min(a, b);
	}

	static int gcd(int a, int b) {
		if (a == 0)
			return b;
		return gcd(b % a, a);
	}

	static int modInverse(int a, int m) {
		int g = gcd(a, m);
		if (g != 1)
			return -1;
		else
			return power(a, m - 2, m);

	}

	// To compute x^y under modulo m
	static int power(int x, int y, int m) {
		if (y == 0)
			return 1;

		int p = power(x, y / 2, m) % m;
		p = (p * p) % m;

		if (y % 2 == 0)
			return p;
		else
			return (x * p) % m;
	}

	static int[] primeGenerator(int num) {
		int length = 0, arr[] = new int[num], a = num, factor = 1;
		if (num % 2 == 0) {
			while (num % 2 == 0) {
				num /= 2;
				factor *= 2;
			}
			arr[length++] = factor;
		}
		for (int i = 3; i * i <= a; i++) {
			factor = 1;
			if (num % i == 0) {
				while (num % i == 0) {
					num /= i;
					factor *= i;
				}
				arr[length++] = factor;
			}
		}
		if (num > 1)
			arr[length++] = num;
		return Arrays.copyOfRange(arr, 0, length);
	}

	static boolean isPrime(int n) {
		// Corner cases
		if (n <= 1)
			return false;
		if (n <= 3)
			return true;

		// This is checked so that we can skip
		// middle five numbers in below loop
		if (n % 2 == 0 || n % 3 == 0)
			return false;

		for (int i = 5; i * i <= n; i = i + 6)
			if (n % i == 0 || n % (i + 2) == 0)
				return false;

		return true;
	}

	
	  static class Scanner { BufferedReader br; StringTokenizer st;
	  
	 Scanner() { br = new BufferedReader(new InputStreamReader(System.in)); }
	  
	  Scanner(String fileName) throws FileNotFoundException { br = new
	  BufferedReader(new FileReader(fileName)); }
	  
	  String next() throws IOException { while (st == null || !st.hasMoreTokens())
	  st = new StringTokenizer(br.readLine()); return st.nextToken(); }
	  
	  String nextLine() throws IOException { return br.readLine(); }
	  
	  int nextInt() throws IOException { return Integer.parseInt(next()); }
	  
	  long nextLong() throws NumberFormatException, IOException { return
	  Long.parseLong(next()); }
	  
	  double nextDouble() throws NumberFormatException, IOException { return
	  Double.parseDouble(next()); }
	  
	  boolean ready() throws IOException { return br.ready(); }
	  
	  }
	 

	static void sort(int[] a) {
		shuffle(a);
		Arrays.sort(a);
	}

	static void shuffle(int[] a) {
		int n = a.length;
		Random rand = new Random();
		for (int i = 0; i < n; i++) {
			int tmpIdx = rand.nextInt(n);
			int tmp = a[i];
			a[i] = a[tmpIdx];
			a[tmpIdx] = tmp;
		}
	}
}

class Pair {
	int x;
	int y;

	Pair(int a, int b) {
		x = a;
		y = b;
	}

	void print() {
		System.out.println(this.x + " " + this.y);
	}
}

class Mod{
	static final int MOD = 998244353;
	
	int add(int x, int y){
		x += y;
	    while(x >= MOD) x -= MOD;
	    while(x < 0) x += MOD;
	    return x;
	}
	
	int subtract(int x, int y) {
		x -= y;
	    while(x >= MOD) x -= MOD;
	    while(x < 0) x += MOD;
	    return x;
	}

	int mul(int x, int y)
	{
		int result = (int)((long)x*y % MOD);
	    return result>=0?result:result+MOD;
	}

	int binpow(int x, int y)
	{
	    int z = 1;
	    while(y!=0)
	    {
	        if((y & 1)!=0) 
	        	z = mul(z, x);
	        x = mul(x, x);
	        y >>= 1;
	    }
	    return z;
	}

	int inv(int x)
	{
	    return binpow(x, MOD - 2);
	}

	int divide(int x, int y)
	{
	    return mul(x, inv(y));
	}
	
	static final int N =200043;
	int[] fact;
	
	Mod() {
		fact = new int[N];
	}
	
	void precalc()
	{
	    fact[0] = 1;
	    for(int i = 1; i < N; i++)
	        fact[i] = mul(fact[i - 1], i);
	}

	int C(int n, int k)
	{
	    return divide(fact[n], mul(fact[k], fact[n - k]));
	}
}
