Chef is playing a game which contains a binary string. 
He can perform one operation only:
- Toggle the i_th bit of the string (0 to 1 or 1 to 0)
By performing operations on the string (can be zero times), you have to convert the string with no adjacent bit being the same.
Can you help chef ?
-----Input:-----
- First line will contain $T$, number of test cases. Then the test cases follow. 
- First line of each test case, contains the size of the  string $N$
- Seond line contains a single line of input, the binary string. 
-----Output:-----
For each testcase, output in a single line answer - the minimum operations.
-----Constraints-----
- $1 \leq T \leq 100$
- $2 \leq |S| \leq 10^3$
-----Sample Input:-----
1
4
1011
-----Sample Output:-----
1
t = int(input())

for _ in range(t):
 n = int(input())
 s = input()
 
 s1 = ""
 s0 = ""
 for i in range(n):
  
  s1+=str(i%2)
  s0+=str((i+1)%2)
 count1=0
 count0=0
 for i in range(n):
  if(s[i] != s1[i]):
   count1+=1
  
  if(s[i]!=s0[i]):
   count0+=1
 print(min(count1,count0))
t = int(input())

for _ in range(t):
 n = int(input())
 s = input()
 
 s1 = ""
 s0 = ""
 for i in range(n):
  
  s1+=str(i%2)
  s0+=str((i+1)%2)
 count1=0
 count0=0
 for i in range(n):
  if(s[i] != s1[i]):
   count1+=1
  
  if(s[i]!=s0[i]):
   count0+=1
 print(min(count1,count0))