Buggy python submission (verdict: Runtime Error):
while True:
    letters = list(input())
    x = 1
    for letter in letters:
        if letters.count(letter) == 2:
            x *= 1
        else:
            x *= 0
    print(["No","Yes"][x])


Fixed submission:
letters = list(input())
x = 1
for letter in letters:
        if letters.count(letter) == 2:
            x *= 1
        else:
            x *= 0
print(["No","Yes"][x])

Buggy python submission (verdict: Runtime Error):
while True:
    letters = list(input("input"))
    x = 1
    for letter in letters:
        if letters.count(letter) == 2:
            x *= 1
        else:
            x *= 0
    print(["No","Yes"][x])


Fixed submission:
letters = list(input())
x = 1
for letter in letters:
        if letters.count(letter) == 2:
            x *= 1
        else:
            x *= 0
print(["No","Yes"][x])

Buggy python submission (verdict: Runtime Error):
letters = list(input())
true_false = 1
for letter in letters:
  if letters.count(letter) == 2:
    true_false　*= 1
  else:
    true_false *= 0
print(["No","Yes"][true_false])


Fixed submission:
letters = list(input())
x = 1
for letter in letters:
        if letters.count(letter) == 2:
            x *= 1
        else:
            x *= 0
print(["No","Yes"][x])

Buggy python submission (verdict: Runtime Error):
letters = list(input())
a = letters[0]
if letters.count(a) == 2:
  if letters[1] == a:
    if letters[2] == letters[3]:
      print("Yes")
    else print("No")
  else:
    b = letters[1]
    if letters.count(b) == 2:
      print("Yes")
    else:
      print("No")
else:
  print("No")

    

Fixed submission:
letters = list(input())
x = 1
for letter in letters:
        if letters.count(letter) == 2:
            x *= 1
        else:
            x *= 0
print(["No","Yes"][x])

Buggy python submission (verdict: Runtime Error):
letters = list(S)
a = letters[0]
if letters.count(a) == 2:
  if letters[1] == a:
    if letters[2] == letters[3]:
      print("Yes")
    else print("No")
  else:
    b = letters[1]
    if letters.count(b) == 2:
      print("Yes")
    else:
      print("No")
else:
  print("No")

    

Fixed submission:
letters = list(input())
x = 1
for letter in letters:
        if letters.count(letter) == 2:
            x *= 1
        else:
            x *= 0
print(["No","Yes"][x])

Buggy python submission (verdict: Runtime Error):
return "Yes"


Fixed submission:
letters = list(input())
x = 1
for letter in letters:
        if letters.count(letter) == 2:
            x *= 1
        else:
            x *= 0
print(["No","Yes"][x])

Buggy python submission (verdict: Runtime Error):
S = list(input())
return "Yes"


Fixed submission:
letters = list(input())
x = 1
for letter in letters:
        if letters.count(letter) == 2:
            x *= 1
        else:
            x *= 0
print(["No","Yes"][x])

Buggy python submission (verdict: Runtime Error):
letters = list(S)
a = letters[0]
if letters.count(a) == 2:
  if letters[1] == a:
    if letters[2] == letters[3]:
      return "Yes"
    else return "No"
  else:
    b = letters[1]
    if letters.count(b) == 2:
      return "Yes"
    else:
      return "No"
else:
  return "No"

    

Fixed submission:
letters = list(input())
x = 1
for letter in letters:
        if letters.count(letter) == 2:
            x *= 1
        else:
            x *= 0
print(["No","Yes"][x])

Buggy python submission (verdict: Runtime Error):
letters = list(S)
a = letters[0]
if letters.count(a) == 2:
  if letters[1] == a:
    if letters[2] == letters[3]:
      return "Yes"
    else return "No"
  else:
    b = letters[1]
    if letters.count(b) == 2:
      return "Yes"
    else:
      return "No"
    

Fixed submission:
letters = list(input())
x = 1
for letter in letters:
        if letters.count(letter) == 2:
            x *= 1
        else:
            x *= 0
print(["No","Yes"][x])

Buggy python submission (verdict: Runtime Error):
S = input()
letters = list(S)
a = letters[0]
if letters.count(a) == 2:
  if letters[1] == a:
    if letters[2] == letters[3]:
      return "Yes"
    else return "No"
  else:
    b = letters[1]
    if letters.count(b) == 2:
      return "Yes"
    else:
      return "No"
    

Fixed submission:
letters = list(input())
x = 1
for letter in letters:
        if letters.count(letter) == 2:
            x *= 1
        else:
            x *= 0
print(["No","Yes"][x])