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.io.*;
import java.lang.reflect.Array;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.math.RoundingMode;
import java.text.DecimalFormat;
import java.util.*;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Main
{	
   static long mod=(long)(1e+9 + 7);
   //static long mod=(long)998244353;
   
   static int[] sieve;
   static ArrayList<Integer> primes;
   static PrintWriter out;
   static fast s;
   static StringBuilder fans;
   
   public static void solve()
   {
   	int n=s.nextInt();
   	long health[]=new long[n];
   	long damage[]=new long[n];
   	
   	for(int i=0;i<n;i++)
   		{
   			health[i]=s.nextLong();
   			damage[i]=s.nextLong();
   		}
   	
   	long right_bullet[]=new long[n];
   	long right_explode[]=new long[n];
   	
   	int chain=0;
   	int index=-1;
   	long min=Long.MAX_VALUE;
   	
   	for(int i=0;i<n;i++) min=Math.min(min, health[i]);
   	
   	for(int i=0;i<n-1;i++)
   		{
   			if(damage[i]<health[i+1])
   				{
   					chain=1;
   					index=i+1;
   					break;
   				}
   		}
   	if(chain==0 && damage[n-1]<health[0])
   		{
   			chain=1;
   			index=0;
   		}
   	
   	if(chain==0)
   		{
   			fans.append(min+"\n");
   		}
   	else
   		{
   		   long a[]=new long[n];
   		   long b[]=new long[n];
   		   
   		   int cnt=0;
   		   for(int i=index;i<n;i++)
   		   	{
   		   		a[cnt]=health[i];
   		   		b[cnt]=damage[i];
   		   		cnt++;
   		   	}
   		   for(int i=0;i<index;i++)
   		   	{
   		   		a[cnt]=health[i];
   		   		b[cnt]=damage[i];
   		   		cnt++;
   		   	}
   		   
   	   	right_bullet[n-1]=a[n-1];
   	   	right_explode[n-1]=0;
   	   	
   	   	for(int i=n-2;i>=0;i--)
   	   		{
   					right_bullet[i]=a[i]+Math.max(0, a[i+1]-b[i])+right_explode[i+1];
   					right_explode[i]=Math.max(0, a[i+1]-b[i])+right_explode[i+1];	
   	   		}
   	   	
   	   	long min1=right_bullet[0];
   	   	
   	   	a[0]-=b[n-1];
   	   	long left[]=new long[n];
   	   	left[0]=a[0];
   	   	
   	   	for(int i=1;i<n;i++)
   	   		{
   	   			if(a[i]<=b[i-1])
   	   				{
   	   					left[i]=left[i-1];
   	   				}
   	   			else
   	   				left[i]=left[i-1]+(a[i]-b[i-1]);
   	   		}
   	   	
   	   	for(int i=1;i<n;i++)
   	   		{
   	   			min1=Math.min(min1, right_bullet[i]+left[i-1]);
   	   		}
   			fans.append(min1+"\n");
   		}
   }
   
   public static void main(String[] args) throws java.lang.Exception
   {	  	
	     s = new fast();
	     out=new PrintWriter(System.out);
	     fans=new StringBuilder("");
		  
	     int t=s.nextInt();
	     
	     while(t>0)
	    	 {
	    		 solve();
	    		 t--;
	    	 }
	    
	    out.println(fans);
	    out.close();
   }
  
 
 
static class fast {   
	
	    private InputStream i;
		private byte[]  buf = new byte[1024];
		private int curChar;
		
		private int numChars;
		
		//Return floor log2n
		public static long log2(long bits) // returns 0 for bits=0
			{
			    int log = 0;
			    if( ( bits & 0xffff0000 ) != 0 ) { bits >>>= 16; log = 16; }
			    if( bits >= 256 ) { bits >>>= 8; log += 8; }
			    if( bits >= 16  ) { bits >>>= 4; log += 4; }
			    if( bits >= 4   ) { bits >>>= 2; log += 2; }
			    return log + ( bits >>> 1 );
			}
		
		public static boolean next_permutation(int a[])
		   {
			   int i=0,j=0;int index=-1;	   
			   int n=a.length;
			   
			   for(i=0;i<n-1;i++)
				   if(a[i]<a[i+1]) index=i;
			   
			   if(index==-1) return false;
			   i=index;
 
			  
			   for(j=i+1;j<n && a[i]<a[j];j++);
 
			   int temp=a[i];
			   a[i]=a[j-1];
			   a[j-1]=temp;
			   	   
			   for(int p=i+1,q=n-1;p<q;p++,q--)
			   {
				   temp=a[p];
				   a[p]=a[q];
				   a[q]=temp;
			   }
			   
			   return true;
		   }
		   
		   
		public static void division(char ch[],int divisor)
		   {
			   int div=Character.getNumericValue(ch[0]); int mul=10;int remainder=0;
			   StringBuilder quotient=new StringBuilder("");
			   for(int i=1;i<ch.length;i++)
			   {
				   div=div*mul+Character.getNumericValue(ch[i]);	
				   if(div<divisor) {quotient.append("0");continue;}
				   quotient.append(div/divisor);
				   div=div%divisor;mul=10;
				   
			   } 
			   remainder=div;
			   while(quotient.charAt(0)=='0')quotient.deleteCharAt(0);	   
			   System.out.println(quotient+" "+remainder);	  
		   }
		
		public static void sieve(int size)
		{
			sieve=new int[size+1];
			
			primes=new ArrayList<Integer>();
			
			sieve[1]=1;
			
			for(int i=2;i*i<=size;i++)
			{
				if(sieve[i]==0)
				 {
					for(int j=i*i;j<size;j+=i) {sieve[j]=1;}
				 }
			}
			
			for(int i=2;i<=size;i++)
			{
				if(sieve[i]==0) primes.add(i);
			}
		}
		
		public static long pow(long n, long b, long MOD)
		   {
		       long x=1;long y=n; 
		       while(b > 0)
		       {
		           if(b%2 == 1)
		           {
		               x=x*y;
		               if(x>MOD) x=x%(MOD);
		           }
		           y = y*y;
		           if(y>MOD) y=y%(MOD); 
		           b >>= 1;
		       }
		       return x;
		   }
 
 
		public static long mod_inv(long n,long mod)
		{
			return pow(n,mod-2,mod);
		}
		
		//Returns index of highest number less than or equal to key
		 public static int upper(long[] a,int length,long key)
		 {
			    int low = 0;
		        int high = length-1;
		        int ans=-1;
		        
		        while (low <= high) {
		            int mid = (low + high) / 2;
		            if (key >= a[mid]) {
		                ans=mid;
		            	low = mid+1;
		            } else if(a[mid]>key){
		                high = mid - 1;
		            }
		        }
		        return ans;
		}
		
		//Returns index of least number greater than or equal to key
		 public static int lower(long[] a,int length,long key)
		 {
			    int low = 0;
		        int high = length-1;
		        int ans=-1;
		        
		        while (low <= high) {
		            int mid = (low + high) / 2;
		            if (key<=a[mid]) {
		                ans=mid;
		            	high = mid-1;
		            }
		            else{
		            		low=mid+1;
		            	}
		        }
		        return ans;
		} 
		   
		public long gcd(long r,long ans)
		{
			if(r==0) return ans;
			return gcd(ans%r,r);
		}
		public fast() {
			this(System.in);
		}
		public fast(InputStream is) {
			i = is;
		}
		public int read() {
			if (numChars == -1)
				throw new InputMismatchException();
			if (curChar >= numChars) {
				curChar = 0;
				try {
					numChars = i.read(buf);
				} catch (IOException e) {
					throw new InputMismatchException();
				}
				if (numChars <= 0)
					return -1;
			}
			return buf[curChar++];
		}
		public String nextLine() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isEndOfLine(c));
			return res.toString();
		}
		public String nextString() {
     		int c = read();
			while (isSpaceChar(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isSpaceChar(c));
			return res.toString();
		}
		public long nextLong() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = read();
			}
			long res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} while (!isSpaceChar(c));
			return res * sgn;
		}
		public int nextInt() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = read();
			}
			int res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} while (!isSpaceChar(c));
			return res * sgn;
		}
		public boolean isSpaceChar(int c) {
			return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
		}
		public boolean isEndOfLine(int c) {
			return c == '\n' || c == '\r' || c == -1;
		}
 
	}	
}