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=input().split()
    k=int(k)
    m=len(n)
    d={}
    i=0
    for i in range(m):
      if n[i] not in d:
        if len(d)==k:
          break
        d[n[i]]=0
      d[n[i]]+=1
    else:
      print(n)
      continue
    n=list(n)
    while True:
      if n[i]=="9" or len(d)==k and max(d)<=n[i]:
        i-=1
        d[n[i]]-=1
        if d[n[i]]==0:
          del d[n[i]]
      else:
        if len(d)<k:
          n[i]=str(int(n[i])+1)
          if n[i] not in d:
            d[n[i]]=0
          d[n[i]]+=1
          p="0" if len(d)<k else min(d)
          for i in range(i+1,m):
            n[i]=p
        else:
          n[i]=min(j for j in d if j>n[i])
          for i in range(i+1,m):
            n[i]=min(d)
        break
    print("".join(n))