Buggy python submission (verdict: Runtime Error):
def sort(str_list):
  for i in range(len(str_list) - 1):
    string = str_list[i]
    for j in range(i + 1, len(str_list)):
      next_string = str_list[j]
      for k in range(len(string)):
        if ord(string[k]) > ord(next_string[k]):
          temp = string
          str_list[i] = next_string
          str_list[j] = temp
          break
        elif ord(string[k]) == ord(next_string[k]):
          continue
        else:
          break
  ans = ""
  for i in str_list:
    ans += i
  return ans
 
line1 = input().split()
n = line1[0]
l = line1[1]
str_list = []
for i in range(n):
  str_list.append(input())
print(sort(str_list))
  
def sort(str_list):
  for i in range(len(str_list) - 1):
    string = str_list[i]
    for j in range(i + 1, len(str_list)):
      next_string = str_list[j]
      for k in range(len(string)):
        if ord(string[k]) > ord(next_string[k]):
          temp = string
          str_list[i] = next_string
          str_list[j] = temp
          break
        elif ord(string[k]) == ord(next_string[k]):
          continue
        else:
          break
  ans = ""
  for i in str_list:
    ans += i
  return ans

line1 = input().split()
n = int(line1[0])
l = line1[1]
str_list = []
for i in range(n):
  str_list.append(input())
print(sort(str_list))

Fixed submission:
def order(str1, str2):
  for i in range(len(str1)):
    if ord(str1[i]) > ord(str2[i]):
      return False
    elif ord(str1[i]) == ord(str2[i]):
      continue
    else:
      return True
 
def sort(str_list):
  for i in range(len(str_list) - 1):
    for j in range(i + 1, len(str_list)):
      if not order(str_list[i], str_list[j]):
        temp = str_list[i]
        str_list[i] = str_list[j]
        str_list[j] = temp
  ans = ""
  for i in str_list:
    ans += i
  return ans
 
line1 = input().split()
n = int(line1[0])
l = line1[1]
str_list = []
for i in range(n):
  str_list.append(input())
print(sort(str_list))

Buggy python submission (verdict: Runtime Error):
def sort(str_list):
  for i in range(len(str_list) - 1):
    string = str_list[i]
    for j in range(i + 1, len(str_list)):
      next_string = str_list[j]
      for k in range(len(string)):
        if ord(string[k]) > ord(next_string[k]):
          temp = string
          str_list[i] = next_string
          str_list[j] = temp
          break
        elif ord(string[k]) == ord(next_string[k]):
          continue
        else:
          break
  ans = ""
  for i in str_list:
    ans += i
  return ans

line1 = input().split()
n = line1[0]
l = line1[1]
str_list = []
for i in range(n):
  str_list.append(input())
print(sort(str_list))
  

Fixed submission:
def order(str1, str2):
  for i in range(len(str1)):
    if ord(str1[i]) > ord(str2[i]):
      return False
    elif ord(str1[i]) == ord(str2[i]):
      continue
    else:
      return True
 
def sort(str_list):
  for i in range(len(str_list) - 1):
    for j in range(i + 1, len(str_list)):
      if not order(str_list[i], str_list[j]):
        temp = str_list[i]
        str_list[i] = str_list[j]
        str_list[j] = temp
  ans = ""
  for i in str_list:
    ans += i
  return ans
 
line1 = input().split()
n = int(line1[0])
l = line1[1]
str_list = []
for i in range(n):
  str_list.append(input())
print(sort(str_list))