description: You are given a string s of length n consisting of characters a and/or b.
  
  Let \operatorname{AB}(s) be the number of occurrences of string ab in s as a substring. Analogically, \operatorname{BA}(s) is the number of occurrences of ba in s as a substring.
  
  In one step, you can choose any index i and replace s_i with character a or b.
  
  What is the minimum number of steps you need to make to achieve \operatorname{AB}(s) = \operatorname{BA}(s)?
  
  Reminder:
  
  The number of occurrences of string d in s as substring is the number of indices i (1 ≤ i ≤ |s| - |d| + 1) such that substring s_i s_{i + 1} ... s_{i + |d| - 1} is equal to d. For example, \operatorname{AB}(aabbbabaa) = 2 since there are two indices i: i = 2 where aabbbabaa and i = 6 where aabbbabaa.
  
  Input
  
  Each test contains multiple test cases. The first line contains the number of test cases t (1 ≤ t ≤ 1000). Description of the test cases follows.
  
  The first and only line of each test case contains a single string s (1 ≤ |s| ≤ 100, where |s| is the length of the string s), consisting only of characters a and/or b.
  
  Output
  
  For each test case, print the resulting string s with \operatorname{AB}(s) = \operatorname{BA}(s) you'll get making the minimum number of steps.
  
  If there are multiple answers, print any of them.
  
  Example
  
  Input
  
  
  4
  b
  aabbbabaa
  abbb
  abbaab
  
  
  Output
  
  
  b
  aabbbabaa
  bbbb
  abbaaa
  
  Note
  
  In the first test case, both \operatorname{AB}(s) = 0 and \operatorname{BA}(s) = 0 (there are no occurrences of ab (ba) in b), so can leave s untouched.
  
  In the second test case, \operatorname{AB}(s) = 2 and \operatorname{BA}(s) = 2, so you can leave s untouched. 
  
  In the third test case, \operatorname{AB}(s) = 1 and \operatorname{BA}(s) = 0. For example, we can change s_1 to b and make both values zero.
  
  In the fourth test case, \operatorname{AB}(s) = 2 and \operatorname{BA}(s) = 1. For example, we can change s_6 to a and make both values equal to 1.
solution: t = int(input())
  from collections import defaultdict as dd
  def find_change(orig: str, new:str) -> tuple:
      orig_score = (1,0) if orig == 'ab' else (0,1) if orig == 'ba' else (0,0)
      new_score = (1,0) if new == 'ab' else (0,1) if new == 'ba' else (0,0)
      return (new_score[0] - orig_score[0], new_score[1] - orig_score[1])
  for _ in range(t):
      s = input().strip()
      ab,ba = 0,0
      for i in range(len(s)-1):
          if s[i] == 'a' and s[i+1] == 'b':
              ab += 1
          elif s[i] == 'b' and s[i+1] == 'a':
              ba += 1
      # find the minimum number of steps needed to make ab == ba
      for i in range(len(s)):
          if ab == ba: break
          change = (0,0)
          c = s[i]
          flipped = 'a' if c == 'b' else 'b'
          if i > 0:
              change = find_change(s[i-1:i+1], s[i-1]+flipped)
          if i < len(s)-1:
              tmp = find_change(s[i:i+2], flipped+s[i+1])
              change = (change[0] + tmp[0], change[1] + tmp[1])
          #greedy
          new_state = (ab + change[0], ba + change[1])
          if abs(new_state[0] - new_state[1]) < abs(ab - ba):
              ab += change[0]
              ba += change[1]
              s = s[:i] + flipped + s[i+1:]
      print(s)
  
  