description: You have an array of integers (initially empty).
  
  You have to perform q queries. Each query is of one of two types: 
  
    * "1 x" — add the element x to the end of the array; 
    * "2 x y" — replace all occurrences of x in the array with y. 
  
  
  
  Find the resulting array after performing all the queries.
  
  Input
  
  The first line contains a single integer q (1 ≤ q ≤ 5 ⋅ 10^5) — the number of queries.
  
  Next q lines contain queries (one per line). Each query is of one of two types: 
  
    * "1 x" (1 ≤ x ≤ 5 ⋅ 10^5); 
    * "2 x y" (1 ≤ x, y ≤ 5 ⋅ 10^5). 
  
  
  
  It's guaranteed that there is at least one query of the first type.
  
  Output
  
  In a single line, print k integers — the resulting array after performing all the queries, where k is the number of queries of the first type.
  
  Examples
  
  Input
  
  
  7
  1 3
  1 1
  2 1 2
  1 2
  1 1
  1 2
  2 1 3
  
  
  Output
  
  
  3 2 2 3 2 
  
  Input
  
  
  4
  1 1
  1 2
  1 1
  2 2 2
  
  
  Output
  
  
  1 2 1 
  
  Input
  
  
  8
  2 1 4
  1 1
  1 4
  1 2
  2 2 4
  2 4 3
  1 2
  2 2 7
  
  
  Output
  
  
  1 3 3 7 
  
  Note
  
  In the first example, the array changes as follows:
  
  [] → [3] → [3, 1] → [3, 2] → [3, 2, 2] → [3, 2, 2, 1] → [3, 2, 2, 1, 2] → [3, 2, 2, 3, 2].
  
  In the second example, the array changes as follows:
  
  [] → [1] → [1, 2] → [1, 2, 1] → [1, 2, 1].
  
  In the third example, the array changes as follows:
  
  [] → [] → [1] → [1, 4] → [1, 4, 2] → [1, 4, 4] → [1, 3, 3] → [1, 3, 3, 2] → [1, 3, 3, 7].
solution: from sys import stdin, stdout
  
  q = int(stdin.readline())
  
  a = [["NIL","NIL"] for i in range(500001)] # points to head and tail of chain
  array_pointer = 0
  
  for _ in range(q):
      content = stdin.readline().split()
  
      if len(content) == 2:
          x = int(content[1])
          block = [array_pointer, "NIL"]
          array_pointer += 1
  
          if a[x][0] == "NIL":
              a[x][0] = block
              a[x][1] = block
  
          else:
              a[x][1][1] = block
              a[x][1] = block
  
      else:
          x, y = int(content[1]), int(content[2])
          if x==y or a[x][0] == "NIL":
              pass
  
          else:
              if a[y][0] == "NIL":
                  a[y][0] = a[x][0]
                  a[y][1] = a[x][1]
                  a[x][0] = "NIL"
                  a[x][1] = "NIL"
              else:
                  a[y][1][1] = a[x][0]
                  a[y][1] = a[x][1]
                  a[x][0] = "NIL"
                  a[x][1] = "NIL"
  
  answer = [0]*array_pointer
  for i in range(1, 500001):
      pointer = a[i][0]
      while pointer != "NIL":
          answer[pointer[0]] = str(i)
          pointer = pointer[1]
  
  stdout.write(' '.join(answer)+'\n')
  