Chef has $K$ chocolates and he wants to distribute them to $N$ people (numbered $1$ through $N$). These people are standing in a line in such a way that for each $i$ ($1 \le i \le N-1$), person $i$ and person $i+1$ are adjacent.
First, consider some way to distribute chocolates such that for each valid $i$, the number of chocolates the $i$-th person would receive from Chef is $A_i$ and the sum $S_1 = \sum_{i=1}^{N-1} \left|A_i - A_{i+1}\right|$ is minimum possible. Of course, each person must receive a non-negative integer number of chocolates.
Then, Chef wants to create a new sequence $B_1, B_2, \ldots, B_N$ by rearranging (permuting) the elements of the sequence $A_1, A_2, \ldots, A_N$. For each valid $i$, the number of chocolates the $i$-th person actually receives from Chef is $B_i$. Chef wants to distribute the chocolates (choose $B_1, B_2, \ldots, B_N$ by permuting the sequence $A$ and give $B_i$ chocolates to the $i$-th person for each valid $i$) in such a way that $S_2 = \sum_{i=1}^{N-1} \left|B_i – B_{i+1}\right|$ is maximum possible. You need to find the maximum value of $S_2$.
It is guaranteed that $S_2$ does not depend on the exact choice of the sequence $A_1, A_2, \ldots, A_N$, as long as it is a sequence that minimises $S_1$.

-----Input-----
- The first line of the input contains a single integer $T$ denoting the number of test cases. The description of $T$ test cases follows.
- The first line of each test case contains a single integer $N$.
- The second line contains a single integer $K$.

-----Output-----
For each test case, print a single line containing one integer — the maximum value of the sum $S_2$.

-----Constraints-----
- $1 \le T \le 10$
- $2 \le N \le 10^5$
- $2 \le K \le 10^{100,000}$

-----Subtasks-----
Subtask #1 (30 points): $2 \le N, K \le 1,000$
Subtask #2 (70 points): original constraints

-----Example Input-----
1
3
2

-----Example Output-----
2

-----Explanation-----
Example case 1: To minimise $S_1$, Chef could give $1$ chocolate to person $1$ and $1$ chocolate to person $2$, so $S_1 = |1-1| + |1-0| = 1$.
To maximise $S_2$, Chef can give $1$ chocolate to person $1$ and $1$ chocolate to person $3$, since the sequence $B = (1, 0, 1)$ is a permutation of $A = (1, 1, 0)$. Then, $S_2 = |1-0| + |0-1| = 2$.

Difficulty: interview

Starter code:

Solutions:
t = int(input())
for _ in range(t):
 n = int(input())
 k = int(input())
 num = int(k/n)
 x = max(n*(1+num) - k, 0)
 diff = abs(x - (n-x))
 if diff == 0:
  number = 2*x - 1
 else:
  number = min(x, n-x)*2
 print(number)

# cook your dish here
t = int(input())
for _ in range(t):
 n = int(input())
 k = int(input())
 num = int(k/n)
 if (k/n == num):
  print(0)
 else:
  x = max(n*(1+num) - k, 0)
  diff = abs(x - (n-x))
  if diff == 0:
   number = 2*x - 1
  else:
   number = min(x, n-x)*2
  print(number)

# cook your dish here
t = int(input())
for _ in range(t):
 n = int(input())
 k = int(input())
 num = int(k/n)
 x = max(n*(1+num) - k, 0)
 diff = abs(x - (n-x))
 if diff == 0:
  number = 2*x - 1
 else:
  number = min(x, n-x)*2
 print(number)

def solve():
 n=int(input())
 k=int(input())
 cnt1=k%n
 cnt0=n-cnt1
 if(cnt1<cnt0):
  print(2*cnt1)
 elif(cnt1>cnt0):
  print(2*cnt0)
 else:
  print(2*cnt1-1)
 

def __starting_point():
 t=int(input())
 for _1 in range(t):
  solve()
__starting_point()

# cook your dish here
def Test():
 n = int(input())
 k = int(input())
 low = min(k%n , n - k % n)
 print(min(n-1 , low*2))
 
T = int(input())
 
for t in range(T):
  Test()

# cook your dish here
testcase = int(input())
for ij in range(testcase):
 n = int(input())
 k = int(input())
 list1 = []
 list2 = []
 list3 = [0]
 if n%2 !=0:
  f = n//2
  for i in range(f):
   list1.append(2*(i+1))
  for i in range(len(list1)):
   list2.append(list1[i])
  for i in range(len(list1)):
   list2.append(list1[f-1-i])

 if n%2 == 0:
  s = (n-1)//2
  
  for i in range(s):
   list1.append(2*(i+1))
  for i in range(s):
   list2.append(list1[i])
  list2.append(list1[s-1]+1)
  for i in range(s):
   list2.append((list1[s-1-i]))
 list2.append(0)

 p = k%n
 print(list2[p-1])













t = int(input())
for test in range(t):
 n = int(input())
 k = int(input())
 one = k % n
 zero = n - one
 if zero < one:
  one, zero = zero, one

 if zero >= one + 1:
  print(one * 2)
 elif zero == one:
  print(2 * zero - 1)
 else:
  print((zero - 1) * 2)



# cook your dish here



t = int(input())
while t!=0:


 n = int(input())
 k = int(input())
 if k%n == 0 :
  print(0)
 else:
  p = k%n
  if n%2==0 and p==n/2:
   print(2*(p)-1)

  elif p>(n//2):
   print(2*(n-p))

  else:
   print(2*(p))


 t-=1

for i in range(int(input())):
 N=int(input())
 K=int(input())
 min1=min(K%N,N-K%N)
 print(min(N-1,min1*2))

for i in range(int(input())):
 N=int(input())
 K=int(input())
 min1=min(K%N,N-K%N)
 print(min(N-1,min1*2))

import sys 
input = sys.stdin.readline 

for _ in range(int(input())):
 N=int(input())
 K=int(input())
 min1=min(K%N,N-K%N)
 print(min(N-1,min1*2))

import sys,math
#sys.setrecursionlimit(100000000)
input = sys.stdin.readline
 
############ ---- USER DEFINED INPUT FUNCTIONS ---- ############
def inp():
 return(int(input()))
def inlt():
 return(list(map(int,input().split())))
def insr():
 s = input()
 return(list(s[:len(s) - 1]))
def invr():
 return(list(map(int,input().split())))
################################################################
############ ---- THE ACTUAL CODE STARTS BELOW ---- ############

t=inp()
for _ in range(t):
 n=inp()
 k=inp()
 x=k%n
 y=n-x
 if x==0:
  print(0)
 elif x==y:
  ans=2*x-1
  print(ans)
 else:
  ans=min(x,y)*2
  print(ans)



for t in range(int(input())):
 n = int(input())
 k = int(input())
 low = min(k % n , n - k % n)
 print(min(n - 1 , low * 2))


for _ in range(int(input())):
 n = int(input())
 k = int(input())
 if (k%n==0):
  print(0)
 elif (n%2==0):
  x = n//2 
  if (k%x==0):
   print(n-1)
  else:
   y = k%n
   if y>x:
    y=n-y
   print(2*y)
 else:
  x=n//2
  y=x+1
  if ( (k-x)%n==0 or (k-y)%n==0 ):
   print(n-1)
  else:
   z = k%n
   if z>x:
    z=n-z
   print(2*z)

t=int(input())
for _ in range(t):
 n=int(input())
 k=int(input())
 x1=k//n
 y1=(x1+1)
 y2=k%n
 x2=n-y2
 ans=0
 i=0
 j=0
 l=[]
 while i<x2 and j<y2:
  if y2>=x2:
   l+=[1,0]
  else:
   l+=[0,1]
  i+=1
  j+=1
 while i<x2:
  l.append(0)
  i+=1
 while j<y2:
  l.append(1)
  j+=1
 ans=0
 for i in range(1,len(l)):
  ans+=abs(l[i]-l[i-1])
 print(ans)


# cook your dish here
T=int(input())
while(T):
 n=int(input())
 k=int(input())
 if k%n==0:
  print(0)
 elif ((k%n)==(n-k%n)):
  print(2*(k%n)-1)
 elif ((k%n)>(n-k%n)):
  print(2*(n-k%n))
 elif ((k%n)<(n-k%n)):
  print(2*(k%n))
 T-=1

t = int(input())
for _ in range(t):
 N = int(input())
 K = int(input())
 num_1 = K % N
 num_0 = N - num_1
 ans = 0
 if num_1 > num_0:
  ans = num_0*2
 elif num_0 > num_1:
  ans = num_1*2
 else:
  ans = num_1*2 -1
 print(ans)

t = int(input())
while(t > 0):
 t = t - 1
 n = int(input())
 k = int(input())
 num_1 = k % n
 num_0 = n - num_1
 ans = 0
 if(num_0 > num_1):
  ans = num_1 * 2
 elif(num_0 < num_1):
  ans = num_0 * 2
 else:
  ans = num_1 * 2 - 1
 print(ans)


T = int(input())
for i in range(T):
 n = int(input())
 k = int(input())
 r = k % n
 if r == n-r:
  print(n-1)
 else:
  print(2*min(r, n-r))


def __starting_point():
 T = int(input())
 while T > 0:
  T = T - 1
  n = int(input())
  num = int(input())
  num = num % n
  num2 = n - num
  if num2 == num:
   print(num * 2 - 1)
  else:
   print(min(num, num2) * 2)

__starting_point()

t = int(input())
while t > 0:
 n = int(input())
 k = int(input())
 high = k % n
 low = n - high
 if high == low:
  ans = 2 * high - 1
  print(ans)
 else: 
  mn = min(high, low)
  ans = 2 * mn
  print(ans)
 t = t - 1




t=int(input())
for i in range(t):
 n=input()
 k=input()
 k=int(k)
 n=int(n)
 w=k%n
 if w==n/2:
  print(n-1)
 else:
  y=n-w
  y=min(y,w)
  print(2*y)


t = int(input())
while t != 0:
 n = int(input())
 k = int(input())
 i = k % n
 if i * 2 == n:
  print(n - 1)
 else:
  print(min(i, n - i) * 2)
 t -= 1

for _ in range(int(input())):
 n = int(input())
 k = int(input())
 if k % n == 0:
  print(0)
 else:
  low = min(k % n, n-k % n)
  print(min(n-1, low*2))

t=int(input())
for i in range(t):
 n=int(input())
 k=int(input())
 a=k%n
 if(n%2==0):
  if(a>n//2):
   a=n-a
   print(2*a)
  elif(a<n//2):
   print(2*a)
  else:
   print(2*a-1)
 else:
  if(a>n//2):
   a=n-a
   print(2*a)
  else:
   print(2*a)