This is my code of Problem B of AtCoder Beginner Contest 191.

atcoder-abc-191-b.py

# 入力
N, X = [int(i) for i in input().split()]
A = [int(i) for i in input().split()]

# 配列A'を用意
Aprime = []
for i in range(N):
  if A[i] != X:
    Aprime.append(A[i])

# 出力(A'が空白の場合を考慮)
if Aprime == []:
  print()
else:
  Aprimestr = ""
  for i in range(len(Aprime)-1):
    Aprimestr += str(Aprime[i]) + " "
  Aprimestr += str(Aprime[-1])
  print(Aprimestr)