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
//package learning;
import java.util.*;
import java.io.*;
import java.lang.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;
public class NitsLocal {
    static ArrayList<String> s1;
    static boolean[] prime;
    static int n = (int)1e7;
    
     static void sieve() {
Arrays.fill(prime	, true);
prime[0] = prime[1] = false;
for(int i = 2 ; i * i <= n ; ++i) {
if(prime[i]) {
for(int k = i * i; k<= n ; k+=i) {
prime[k] = false;
}
}
}
 
}
    public static void main(String[] args) {
        InputReader sc = new InputReader(System.in);
        n *= 2;
           prime  = new boolean[n + 1];
           //sieve();
                prime[1] = false;
              
                  
             /*    
        int n = sc.ni();
        int k = sc.ni();
        int []vis = new int[n+1];
        int []a = new int[k];
        for(int i=0;i<k;i++)
        {
            a[i] = i+1;
        }
        int j = k+1;
        int []b = new int[n+1];
        for(int i=1;i<=n;i++)
        {
            b[i] = -1;
        }
        int y = n - k +1;
        int tr = 0;
        int y1 = k+1;
        while(y-- > 0)
        {
        System.out.print("? ");
        for(int i=0;i<k;i++)
        {
            System.out.print(a[i] + " ");
        }
        
        System.out.flush();
        int pos = sc.ni();
        int a1 = sc.ni();
        b[pos] = a1;
        
        
        for(int i=0;i<k;i++)
        {
            if(a[i] == pos)
            {
                a[i] = y1;
                y1++;
            }
        }
        }
        ArrayList<Integer> a2 = new ArrayList<>();
        if(y >= k)
        {
            
        int c = 0;
        int k1 = 0;
            for(int i=1;i<=n;i++)
            {
                if(b[i] != -1)
                {
                    c++;
                    a[k1] = i;
                    a2.add(b[i]);
                    k1++;
                }
                if(c==k)
                    break;
            }
            
            Collections.sort(a2);
            System.out.print("? ");
        for(int i=0;i<k;i++)
        {
            System.out.print(a[i] + " ");
        }
        System.out.println();
        System.out.flush();
        int pos = sc.ni();
        int a1 = sc.ni();
        int ans = -1;
        for(int i=0;i<a2.size();i++)
        {
            if(a2.get(i) == a1)
            {
                ans = i+1;
                break;
            }
        }
        System.out.println("!" + " " + ans);
           System.out.flush();  
        }
        else
        {
            int k1 = 0;
            a = new int[k];
             for(int i=1;i<=n;i++)
            {
                if(b[i] != -1)
                {
                    
                    a[k1] = i;
                    a2.add(b[i]);
                    k1++;
                }
             
            }
              for(int i=1;i<=n;i++)
            {
                if(b[i] == -1)
                {
                    
                    a[k1] = i;
                    
                    k1++;
                    if(k1==k)
                        break;
                }
             
            }
              int ans = -1;
              while(true)
              {
                   System.out.print("? ");
                     for(int i=0;i<k;i++)
                   {
                         System.out.print(a[i] + " ");
                  }
                   System.out.println();
                   System.out.flush();
                   int pos = sc.ni();
                   int a1 = sc.ni();
                   int f = 0;
                   
                   if(b[pos] != -1)
                   {
                       Collections.sort(a2);
                       for(int i=0;i<a2.size();i++)
                       {
                           if(a2.get(i) == a1)
                           {
                               ans = i+1;
                               f = 1;
                               System.out.println("!" + " " + ans);
                               System.out.flush();
                               break;
                           }
                       }
                       if(f==1)
                           break;
                   }
                   else
                   {
                       b[pos] = a1;
                        a = new int[k];
                        a2.add(a1);
             for(int i=1;i<=n;i++)
            {
                if(b[i] != -1)
                {
                    
                    a[k1] = i;
                    a2.add(b[i]);
                    k1++;
                }
             
            }
              for(int i=1;i<=n;i++)
            {
                if(b[i] == -1)
                {
                    
                    a[k1] = i;
                    
                    k1++;
                    if(k1==k)
                        break;
                }
             
                       
                   }
              }
        }  
          */
             
 
    /*
          int n = sc.ni();
          int []a = sc.nia(n);
          int []b = sc.nia(n);
          Integer []d = new Integer[n];
          int []d1 = new int[n];
          for(int i=0;i<n;i++)
          {
              d[i] = (a[i] - b[i]);
             
          }
          int l = 0;
          int r = n-1;
          Arrays.sort(d);
          long res = 0;
          while(l < r)
          {
              if(d[l] + d[r] > 0)
              {
                  res += (long) (r-l);
                  r--;
              }
              else 
                  l++;
          }
          
          w.println(res);
*/
      /*
      int n = sc.ni();
     
      ArrayList<Integer> t1 = new ArrayList<>();
      int []p1 = new int[n+1];
      int []q1 = new int[n-1];
      int []q2 = new int[n-1];
      for(int i=0;i<n-1;i++)
      {
          int p = sc.ni();
          int q = sc.ni();
          t1.add(q);
          p1[p]++;
          q1[i] = p;
          q2[i] = q;
          
      }
      int res = 0;
      for(int i=0;i<t1.size();i++)
      {
          if(p1[t1.get(i)] == 0)
          {
              res = t1.get(i);
              //break;
          }
      }
      
    int y = 1;
    for(int i=0;i<n-1;i++)
    {
        if(q2[i] == res)
        {
            w.println("0");
        }
        else
        {
            w.println(y + " ");
            y++;
        }
    }
      */
 /*
   int n = sc.ni();
   int k = sc.ni();
   Integer []a = new Integer[n];
   for(int i=0;i<n;i++)
   {
       a[i] = sc.ni();
       a[i] = a[i]%k;
   }
   HashMap<Integer,Integer> hm = new HashMap<>();
   for(int i=0;i<n;i++)
   {
       if(!hm.containsKey(a[i]))
           hm.put(a[i], 1);
       else
           hm.put(a[i], hm.get(a[i]) + 1);
   }
  Arrays.sort(a);
  int z = 0;
  long res = 0;
  HashMap<Integer,Integer> v = new HashMap<>();
  for(int i=0;i<n;i++)
  {
      if(a[i] == 0)
          res++;
      else
      {
          if(a[i] == k-a[i] && !v.containsKey(a[i]))
          {
              res += (long) hm.get(a[i]) / 2;
              v.put(a[i],1);
          }
          else
          {
          if(hm.containsKey(a[i]) && hm.containsKey(k-a[i]))
          {
          int temp = a[i];
          
          if(!v.containsKey(a[i]) && !v.containsKey(k-a[i]))
          {
             res += (long) Math.min(hm.get(temp), hm.get(k-temp));
             v.put(temp,1);
             v.put(k-temp,1);
          }
          }
          }
      }
  }
  w.println(res);
*/
 /*
int []a = new int[4];
//G0
a[0] = 0;
a[1] = 1;
a[2] = 0;
a[3] = 1;
int []b = new int[4];
//g1
b[0] = 0;
b[1] = 1;
b[2] = 1;
b[3] = 0;
int [][]dp1 = new int[4][4];
int [][]dp2 = new int[4][4];
for(int i=0;i<4;i++)
{
    for(int j=0;j<4;j++)
    {
        dp1[i][j] = (a[i] | a[j]);
    }
   // w.println();
}
w.println();
for(int i=0;i<4;i++)
{
    for(int j=0;j<4;j++)
    {
        dp2[i][j] = (b[i] | b[j]);
    }
    //w.println();
}
int a1 = 0;
int b1 = 0;
int c1 = 0;
int d1 = 0;
for(int i=0;i<4;i++)
{
    for(int j=0;j<4;j++)
    {
        if(dp1[i][j] == 0 && dp2[i][j] == 0)
            a1++;
        else  if(dp1[i][j] == 1 && dp2[i][j] == 1)
            b1++;
        else  if(dp1[i][j] == 0 && dp2[i][j] == 1)
            c1++;
        else
            d1++;
       
    }
}
w.println(a1+ " " + b1 + " " + c1 +" "+ d1);
*/
 int t = sc.ni();
 while(t-- > 0)
 {
     int n = sc.ni();
     Coin []c = new Coin[n];
     long []a = new long[n];
     long []diff = new long[n];
     for(int i=0;i<n;i++)
     {
         c[i] = new Coin(sc.nl(),sc.nl());
     }
     //Arrays.sort(c,new multipliers1());
   
     int ind = -1;
      long []pre = new long[n];
     for(int i=0;i<n;i++)
     {
        a[i] = c[i].a;
        diff[i] = c[(i+1)%n].a - c[i].b;
        if(diff[i] < 0)
            diff[i] = 0;
        pre[i] = diff[i];
     }
     
      
    for(int i=n-2;i>=0;i--)
    {
        diff[i] += diff[i+1];
    }
   for(int i=1;i<n;i++)
   {
       pre[i] += pre[i-1];
   }
    long min = a[0] + diff[0]- diff[n-1];
     for(int i=1;i<n;i++)
     {
         if(i==1)
         min = Math.min(min, a[i] + diff[(i)%n]);
         else
         {
              min = Math.min(min, a[i] + diff[(i)%n] + pre[i-2]);
         }
     }
        
    
    
   
    
    w.println(min);
    
     
     
     
  
        
 }
 
 
       w.close();
       
        
    
    
} 
    static HashMap<Long,Integer> map;
  
          
    static class Coin{
        long a;
        long b;
        
        Coin(long a, long b)
        {
            this.a = a;
            this.b = b;
           
        }
    }
    static ArrayList<Long> fac;
    static HashSet<Long> hs;
    public static void primeFactors(long n) 
    { 
        // Print the number of 2s that divide n 
        while (n % 2 == 0) { 
            fac.add(2l);
            hs.add(2l);
            n /= 2; 
        } 
  
        // n must be odd at this point.  So we can 
        // skip one element (Note i = i +2) 
        for (long i = 3; i*i <= n; i += 2) { 
            // While i divides n, print i and divide n 
            while (n % i == 0) { 
                fac.add(i);
                hs.add(i);
                n /= i; 
            } 
        } 
  
        // This condition is to handle the case whien 
        // n is a prime number greater than 2 
        if (n > 2) 
            fac.add(n);
    } 
   static int smallestDivisor(int n)  
{  
    // if divisible by 2  
    if (n % 2 == 0)  
        return 2;  
  
    // iterate from 3 to sqrt(n)  
    for (int i = 3; i * i <= n; i += 2) {  
        if (n % i == 0)  
            return i;  
    }  
  
    return n;  
}  
 static boolean IsP(String s,int l,int r)
 {
      while(l <= r)
      {
          if(s.charAt(l) != s.charAt(r))
          {
              return false;
          }
         l++;
         r--;
      }
      return true;
 }
  
	

    
    
 static class Student{
    int id;
    int val;
     Student(int id,int val)
     {
      this.id = id;
      this.val = val;
     }
 }
   
   
   
 
     static int upperBound(ArrayList<Integer> a, int low, int high, int element){
    while(low < high){
        int middle = low + (high - low)/2;
        if(a.get(middle) >= element)
            high = middle;
        else 
            low = middle + 1;
    }
    return low;
}
   static long func(long t,long e,long h,long a, long b)
   {
       if(e*a >= t)
           return t/a;
       else
       {
           return e + Math.min(h,(t-e*a)/b);
       }
   }
         
      
    public static int upperBound(int []arr,int n,int num)
    {
        int l = 0;
        int r = n;
        while(l < r)
        {
            int mid = (l+r)/2;
            if(num >= arr[mid])
            {
                l = mid +1;
            }
            else
                r = mid;
        }
        return l;
    }
    public static int countSetBits(int number){
        int count = 0;
        while(number>0){
            ++count;
            number &= number-1;
        }
        return count;
    }
    
     
      
 
    
   
     static long modexp(long x,long n,long M)
{
    long power = n;
    long result=1;
    x = x%M;
    while(power>0)
    {
        if(power % 2 ==1)
            result=(result * x)%M;
        x=(x*x)%M;
        power = power/2;
    }
    return result;
}
      static long modInverse(long A,long M)
{
    return modexp(A,M-2,M);
}
    static long gcd(long a,long b)
    {
        if(a==0)
            return b;
        else
            return gcd(b%a,a);
    }
    static class Temp{
        int a;
        int b;
        int c;
        int d;
      
        Temp(int a,int b,int c,int d)
        {
            this.a = a;
            this.b = b;
            this.c  =c;
            this.d = d;
            //this.d = d;
        }
    }
   
    
    
   static long sum1(int t1,int t2,int x,int []t)
   {
       int mid = (t2-t1+1)/2;
  if(t1==t2)
      return 0;
    
   else
   return sum1(t1,mid-1,x,t) + sum1(mid,t2,x,t);
    
     
   }
  
   
    static String replace(String s,int a,int n)
    {
        char []c = s.toCharArray();
        for(int i=1;i<n;i+=2)
        {
            int num = (int) (c[i] - 48);
            num += a;
            num%=10;
            c[i] = (char) (num+48);
        }
        return new String(c);
    }
    static String move(String s,int h,int n)
    {
        h%=n;
        char []c = s.toCharArray();
        char []temp = new char[n];
        for(int i=0;i<n;i++)
        {
            temp[(i+h)%n] = c[i];
        }
        return new String(temp);
    }
    
     public static int ip(String s){
return Integer.parseInt(s);
}
     static class multipliers implements Comparator<Long>{
  
         
  public int compare(Long a,Long b) {
   if(a<b)
    return 1;
   else if(b<a)
    return -1;
   else
    return 0;
  }
 }
     
     static class multipliers1 implements Comparator<Coin>{
  
  public int compare(Coin a,Coin b) {
   if(a.a < b.a)
       return -1;
   else if(a.a > b.a)
       return 1;
   else return 0;
       
  
 }
     }
    // Java program to generate power set in 
// lexicographic order. 
 
    
    
    
      static class InputReader {
 
private final InputStream stream;
private final byte[] buf = new byte[8192];
private int curChar, snumChars;
 
public InputReader(InputStream st) {
this.stream = st;
}
 
public int read() {
if (snumChars == -1)
throw new InputMismatchException();
if (curChar >= snumChars) {
curChar = 0;
try {
snumChars = stream.read(buf);
} catch (IOException e) {
throw new InputMismatchException();
}
if (snumChars <= 0)
return -1;
}
return buf[curChar++];
}
 
public int ni() {
int c = read();
while (isSpaceChar(c)) {
c = read();
}
int sgn = 1;
if (c == '-') {
sgn = -1;
c = read();
}
int res = 0;
do {
res *= 10;
res += c - '0';
c = read();
} while (!isSpaceChar(c));
return res * sgn;
}
 
public long nl() {
int c = read();
while (isSpaceChar(c)) {
c = read();
}
int sgn = 1;
if (c == '-') {
sgn = -1;
c = read();
}
long res = 0;
do {
res *= 10;
res += c - '0';
c = read();
} while (!isSpaceChar(c));
return res * sgn;
}
 
public int[] nia(int n) {
int a[] = new int[n];
for (int i = 0; i < n; i++) {
a[i] = ni();
}
return a;
}
 
public String rs() {
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 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 boolean isSpaceChar(int c) {
return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
}
 
private boolean isEndOfLine(int c) {
return c == '\n' || c == '\r' || c == -1;
}
 
}
 
 
 
 
 
   
static PrintWriter w = new PrintWriter(System.out);
                  static class Student1
    {
        int id;
        //int x;
       
       int b;
      
        //long z;
        
        Student1(int id,int b)
        {
            this.id = id;
            //this.x = x;
            //this.s = s;
            this.b = b;
          
           // this.z = z;
            
            
            
           
        }
        
    }
}