description: It is a simplified version of problem F2. The difference between them is the constraints (F1: k ≤ 2, F2: k ≤ 10).
  
  You are given an integer n. Find the minimum integer x such that x ≥ n and the number x is k-beautiful.
  
  A number is called k-beautiful if its decimal representation having no leading zeroes contains no more than k different digits. E.g. if k = 2, the numbers 3434443, 55550, 777 and 21 are k-beautiful whereas the numbers 120, 445435 and 998244353 are not.
  
  Input
  
  The first line contains one integer t (1 ≤ t ≤ 10^4) — the number of test cases. Then t test cases follow.
  
  Each test case consists of one line containing two integers n and k (1 ≤ n ≤ 10^9, 1 ≤ k ≤ 2).
  
  Output
  
  For each test case output on a separate line x — the minimum k-beautiful integer such that x ≥ n.
  
  Example
  
  Input
  
  
  4
  1 1
  221 2
  177890 2
  998244353 1
  
  
  Output
  
  
  1
  221
  181111
  999999999
solution: for _ in range(int(input())):
      n,k=map(int,input().split())
      n=str(n)
      stack=[['',0]]
      l=len(n)
      store=""
      while stack:
          num,loop =stack.pop()
          if len(num) ==l and len(set(num)) <=k:
              store=num
              break
          flag =0
          for i in range(loop,10):
              nn=num +str(i)
              if int(nn) >=int(n[:len(num)+1]) and len(set(nn)) <=k:
                  stack.append([nn,0])
                  flag =1
                  break
          if flag ==0:
              stack.append([num[:-1],int(num[-1])+1])
      print(store)