Problem:
 Score : 100 points    Problem Statement Decades have passed since the beginning of AtCoder Beginner Contest.  The contests are labeled as ABC001 , ABC002 , ... from the first round, but after the 999 -th round ABC999 , a problem occurred: how the future rounds should be labeled?  In the end, the labels for the rounds from the 1000 -th to the 1998 -th are decided: ABD001 , ABD002 , ... , ABD999 .  You are given an integer N between 1 and 1998 (inclusive). Print the first three characters of the label of the N -th round of AtCoder Beginner Contest.      Constraints  1 \leq N \leq 1998  N is an integer.         Input Input is given from Standard Input in the following format:  N       Output Print the first three characters of the label of the N -th round of AtCoder Beginner Contest.        Sample Input 1 999      Sample Output 1 ABC  The 999 -th round of AtCoder Beginner Contest is labeled as ABC999 .       Sample Input 2 1000      Sample Output 2 ABD  The 1000 -th round of AtCoder Beginner Contest is labeled as ABD001 .       Sample Input 3 1481      Sample Output 3 ABD  The 1481 -th round of AtCoder Beginner Contest is labeled as ABD482 .

Solution (Python):
if int(input()) <= 999:
   print('ABC')
else:
   print('ABD')

Solution (Python):
if int(input())<=999:
    print("ABC")
else:
    print("ABD")

Solution (Python):
n=int(input())

if n<1000:
    print("ABC")
else:
    print("ABD")

Solution (Python):
n=int(input())

if n<=999:
    print("ABC")
else:
    print("ABD")

Solution (Python):
n = int(input())
if n <= 999:
  print("ABC")
else:
  print("ABD")

Solution (Python):
N = int(input())
print("ABC") if N < 1000 else print("ABD")

Solution (Python):
n = int(input())
print('ABC' if n <= 999 else 'ABD')

Solution (Python):
n = int(input())
if(n < 1000): print('ABC')
else: print('ABD')

Solution (Python):
N = int(input())
if N<1000:
    print("ABC")
else:
    print("ABD")

Solution (Python):
n = int(input())
print("ABC" if n <= 999 else "ABD")

Solution (Python):
n = int(input())
if n >= 1000:
    print('ABD')
else:
    print('ABC')

Solution (Python):
moji = int(input())
print(("ABC","ABD")[moji >=1000])

Solution (Python):
def main():
    n = int(input())
    print("ABC" if n < 1000 else "ABD")


main()

Solution (Python):
N=int(input())
if N<=999:
  print('ABC')
else:
  print('ABD')

Solution (Python):
N = int(input())
S = 'ABC'
if 1000 <= N <= 1998:
    S = 'ABD'

print(S)

Solution (Python):
N = int(input())

if N < 1000:
    print('ABC')
else:
    print('ABD')

Solution (Python):
X = int(input())

if X < 1000:
  print('ABC')
else:
  print('ABD')

Solution (Python):
N = int(input())
print('ABC' if N <= 999 else 'ABD')

Solution (Python):
n = int(input())

if n <= 999:
  print('ABC')
elif n <= 1998:
  print('ABD')

Solution (Python):
print(["ABC","ABD"][len(input())>3])

Solution (Python):
n=int(input())

if n<=999:
    ans="ABC"
else:
    ans="ABD"
print(ans)

Solution (Python):
n = int(input())
if n < 1000:
  print("ABC")
else:
  print("ABD")

Solution (Python):
n = int(input())

if n > 0 and n < 1000:
    print('ABC')
elif n >= 1000 and n <= 1998:
    print('ABD')

Solution (Python):
n=int(input())
if n>=1000:
  print('ABD')
else:
  print('ABC')

Solution (Python):
import sys
import heapq

def input():
    return sys.stdin.readline().rstrip()


def main():
    N =int(input())

    if N>999:
        print("ABD")
    else:
        print("ABC")









if __name__ == "__main__":
    main()

Solution (Python):
n = int(input())

if n <= 999:
    print("ABC")
elif n > 999:
    print("ABD")

Solution (Python):
print("ABC" if int(input()) < 1000 else "ABD")

Solution (Python):
n=int(input())
if n>999:
    print("ABD")
else:
    print("ABC")

Solution (Python):
print(["ABC","ABD"][int(input())//1000])

Solution (Python):
n = int(input())
if 1 <= n and n <= 999:
    print('ABC')
else:
    print('ABD')

Solution (Python):
n = int(input())
if(n<=999):
  print("ABC")
else:
  print("ABD")

Solution (Python):
n = int(input())
if n <1000:
  print("ABC")
else:
  print("ABD")

Solution (Python):
N=int(input())
if N<1000:
    print("ABC")
else:
    print("ABD")

Solution (Python):
a = int(input())
if a < 1000:
  print('ABC')
else:
  print('ABD')

Solution (Python):
N = int (input ())

if N <= 999:
    print ("ABC")

else:
    print ("ABD")

Solution (Python):
number = int(input())

answer = ''
if number < 1000:
    answer = 'ABC'
else:
    answer = 'ABD'

print(answer)

Solution (Python):
n = int(input())
if n > 999:
  print("ABD")
else:
  print("ABC")

Solution (Python):
n=int(input())
if n<=999:
    print("ABC")
else:
    print("ABD")

Solution (Python):
n = int(input())
if n<1000:
    print("ABC")
else:
    print("ABD")

Solution (Python):
n = int(input())
if n<1000:
    print("ABC")
else:
    print("ABD")

Solution (Python):
a='ABD'
if int(input())<1000:a='ABC'
print(a)

Solution (Python):
n=int(input())
if n<=999:
    print("ABC")
else:
    print("ABD")

Solution (Python):
N = int(input())

print('ABC') if N < 1000 else print('ABD')

Solution (Python):
N = int(input())
print("ABC" if N <= 999 else "ABD")

Solution (Python):
n = int(input())
if n <= 999:
    print('ABC')
else:
    print('ABD')

Solution (Python):
N = int(input())
if N <= 999:
    print('ABC')
else:
    print('ABD')

Solution (Python):
N = int(input())
if 1 <= N <= 999:
    print("ABC")
else:
    print("ABD")

Solution (Python):
def main():
    n = int(input())

    if n < 1000:
        print("ABC")
    else:
        print("ABD")


if __name__ == "__main__":
    main()

Solution (Python):
n = int(input())

if n < 1000:
    ans = 'ABC'
else:
    ans = 'ABD'

print(ans)

Solution (Python):


N = int(input())

if 1 <= N < 1000:
    print('ABC')
elif 1000<= N < 1999:
    print('ABD')
elif N <= 0 or 1999 <= N:
    print('Out of range')

Solution (Python):
N = int(input())

if N <= 999:
    print('ABC')
else:
    print('ABD')

Solution (Python):

n=int(input())
if n < 1000:
    print('ABC')
else:
    print('ABD')

Solution (Python):
N = int(input())

if 1 <= N <= 999:
    print('ABC')
else:
    print('ABD')

Solution (Python):
N = int(input())
if N <= 999:
    print('ABC')
else:
    print('ABD')

Solution (Python):
n = int(input())
if 1 <= n and n <= 999:
  print("ABC")
else:
  print("ABD")

Solution (Python):
n = int(input())

if n >= 1000:
    print('ABD')
else:
    print('ABC')

Solution (Python):
N=int(input())
if N<1000:
    print("ABC")
else:
    print("ABD")

Solution (Python):
if int(input()) < 1000:
  print("ABC")
else:
  print("ABD")

Solution (Python):
n = int(input())


if n<=999 :
    c = 'ABC'
else :
    c = 'ABD'

print(c)

Solution (Python):
N = int(input())

if 1 <= N < 1000:
    print('ABC')
else:
    print('ABD')

Solution (Python):

N = int(input())


if N < 1000:
    print('ABC')
elif 1000 <= N <= 1998:
    print('ABD')
else:
    print('IDK')

Solution (Python):
contest_N = int(input())

if contest_N >= 1000:
    print('ABD')
else:
    print('ABC')

Solution (Python):
N = int(input())

if N < 1000:
    print('ABC')

else :
    print('ABD')

Solution (Python):
contest_num = int(input())

if contest_num >= 1999:
    result_str = 'The contest has not been held'

elif contest_num < 1000:
    result_str = 'ABC'

elif contest_num >= 1000:
    result_str = 'ABD'

print(result_str)

Solution (Python):
N = input()
x = int(N)

if x > 0 and x < 1000:
    answer = 'ABC'
elif x >= 1000 and x <= 1998:
    answer = 'ABD'

print(answer)

Solution (Python):
N = int(input())

if N < 1000:
    print("ABC")
else:
    print("ABD")

Solution (Python):

N = int(input())

if N <= 999:
    print("ABC")
elif 1000 <= N <=1998:
    print("ABD")

Solution (Python):
N=int(input())

if N<=999:
  print('ABC')
else:
  print('ABD')

Solution (Python):



x=input()
i=int(x)


if i<1000 :
    print('ABC')
elif i<=1998:
    print('ABD')

Solution (Python):
N = int(input())

if N <= 999:
    print('ABC')
elif N >999:
    print('ABD')

Solution (Python):
N = int(input())

if N >= 1000:
    print("ABD")
if N < 1000:
    print("ABC")

Solution (Python):
N = int(input())

if N < 1000:
    print("ABC")
else:
    print("ABD")

Solution (Python):
N = int (input())

if N < 1000:
    print('ABC')
elif N >= 1000:
    print('ABD')

Solution (Python):


N = int ( input ( ) )

if 1 <= N <= 999:
    print("ABC")
elif 1000 <= N <= 1998:
    print("ABD")
else:
    print("入力ミス")

Solution (Python):
n=int(input())
if n>=1000:
  print("ABD")
else:
  print("ABC")

Solution (Python):










N = int(input())



if 1<= N <= 999:
    print("ABC")
elif 1000 <= N <= 1998:
    print("ABD")

Solution (Python):
N = int(input())

if N < 1000:
    print("ABC")
else:
    print("ABD")

Solution (Python):
n = int(input())
if n<=999:
  print("ABC")
else:
  print("ABD")

Solution (Python):
N = int(input(""))
if N <= 999:
    print("ABC")
elif 1000 <= N <= 1998:
    print("ABD")
else:
    print("error")

Solution (Python):
n=int(input())
x=n-999 if n>999 else n
if n>999:
    print("ABD")
else:
    print("ABC")

Solution (Python):
if int(input()) < 1000:
  print("ABC")
else:
  print("ABD")

Solution (Python):
N = int(input())

if N < 1000:
    print("ABC")
else:
    print("ABD")

Solution (Python):
N = int(input())
if 1 <= N <= 999:
    print("ABC")
elif 1000 <= N <= 1998:
    print("ABD")

Solution (Python):
N = int(input())
if 1 <= N <= 999:
    print('ABC')
elif 1000 <= N <= 1998:
    print('ABD')

Solution (Python):



N = int(input())





if N < 1000:
    print('ABC')
elif 1000 <= N <= 1998:
    print('ABD')

Solution (Python):

N = int(input())
if N >= 1000:
    print("ABD")
else:
    print("ABC")

Solution (Python):


N = int(input())

if N < 1000:
    print('ABC')

else :
    print('ABD')

Solution (Python):
n=int(input())
print('ABC' if n <=999 else "ABD")

Solution (Python):
N = int(input())

if N <= 999 :
    print('ABC')

else:
    print('ABD')

Solution (Python):
N = int(input())

if N <= 999:
    print('ABC')
else:
    print('ABD')

Solution (Python):
n = int(input())
print("ABC" if n<1000 else "ABD")

Solution (Python):
N = input()
x = int(N)

if x > 0 and x < 1000:
    answer = 'ABC'
elif x >= 1000 and x <= 1998:
    answer = 'ABD'

print(answer)

Solution (Python):
N = int(input())

if N < 1000:
    print("ABC")
else:
    print("ABD")

Solution (Python):
n=int(input())
if(n<=999):
    print("ABC")
else:
    print("ABD")

Solution (Python):
N = int(input())
if N<=999:
    print("ABC")
else:
    print("ABD")

Solution (Python):
N=int(input())

if N<=999:
  print("ABC")
else:
  print("ABD")

Solution (Python):
N = int(input())

if N <= 999:
    print("ABC")
elif N <= 1998:
    print("ABD")

Solution (Python):
N = int(input())

if N >= 1999: 
    print('The contest has not been held')

elif N < 1000:
    print('ABC')

elif N >= 1000:
    print('ABD')

Solution (Python):
N = contest_numer =int(input())
if contest_numer > 999 and 1998 >= contest_numer:
    print("ABD")

elif contest_numer > 0 and 999 >= contest_numer:
    print("ABC")

else:
    print("contest that you inputted now has not been held")

Solution (Python):
integer = int(input())

if integer <= 999:
    print('ABC')
else:
    print('ABD')

Solution (Python):
number = int( input() )

if number >= 1000:
    print('ABD')
else:
    print('ABC')

Solution (Python):



N = int(input())

if N >= 1000:
    print('ABD')
else:
    print('ABC')

Solution (Python):





N = int(input())

if N < 1000:
    print('ABC')
else:
    print('ABD')

Solution (Python):
N = int(input())

if 1 <= N <= 999:
    print("ABC")
elif 1000 <= N <= 1998:
    print("ABD")

Solution (Python):
N = int(input())

if 999 >= N >= 1:
    print("ABC")
if 1998 >= N >= 1000:
    print("ABD")

Solution (Python):
n = int(input())

if n <= 999:
    print('ABC')
else:
    print('ABD')

Solution (Python):





N = int(input())

if N <= 999:
    print('ABC')
elif N >= 1000 and N <= 1998:
    print('ABD')

Solution (Python):
N = int(input())

if N < 1000:
    print('ABC')
else:
    print('ABD')

Solution (Python):



N = int(input())

result = 'ABC'

if 1000 <= N <= 1998:
    result = 'ABD'

print(result)

Solution (Python):

n=input()


if int(n)<=999:
    print('ABC')
else:
    print('ABD')

Solution (Python):
name=int(input())
if name>=1000:
    print('ABD')
else:
    print('ABC')

Solution (Python):
N = int(input())

if N <= 999:
    print('ABC')

elif N <= 1998:
    print('ABD')

Solution (Python):
N=input()
N=int(N)
if N<1000:
    print('ABC')
else:
    print('ABD')

Solution (Python):
N=input()
N=int(N)
if N<1000:
    print('ABC')
elif N>=1000:
    print('ABD')

Solution (Python):
n = int(input())

if n > 999:
    print('ABD')
else:
    print('ABC')

Solution (Python):
n = int(input())
if n <= 999:
    print("ABC")
else:
    print("ABD")

Solution (Python):
N = int(input().rstrip())
if N<1000:
    print("ABC")
else:
    print("ABD")

Solution (Python):
num = int(input())

if num < 1000:
    print('ABC')
else:
    print('ABD')

Solution (Python):
a=int(input())
if a<1000:
  print("ABC")
else:
  print("ABD")

Solution (Python):
n = int(input())

if n>999:
    print("ABD")
else:
    print("ABC")

Solution (Python):
N=int(input())

if N>=1000:
    print('ABD')
else:
    print('ABC')

Solution (Python):
N=input()

if int(N) >= 1000:
    print('ABD')


else:
    print('ABC')

Solution (Python):
N = input()

if int(N)>= 1000:
    print("ABD")

else:
    print("ABC")

Solution (Python):
N = int(input())

if N < 1000:
    print('ABC')
else:
    print('ABD')

Solution (Python):
N = int(input())

if N <= 999:
    print('ABC')

else:
    print('ABD')

Solution (Python):
n = int(input())
if n < 1000:
    print("ABC")
else:
    print("ABD")

Solution (Python):
N = int(input())

if N < 1000:
    print("ABC")
else:
    print("ABD")

Solution (Python):
N = int(input())
if N < 1000:
    print("ABC")
else:
    print("ABD")

Solution (Python):
n = int(input())

if n < 1000:
    print("ABC")
else:
    print("ABD")

Solution (Python):
N = int(input())

if (1 <= N <= 1998):
    if 1 <= N <= 999:
        print('ABC')
    elif 1000 <= N <= 1998:
        print('ABD')

Solution (Python):
N = int(input())

if N <= 999:
  print("ABC")
else:
  print("ABD")

Solution (Python):
N = int(input())

if N >= 1000:
    print( 'ABD' )

else :
    print( 'ABC' )

Solution (Python):
N = int(input())

if N < 1000:
    print('ABC')
elif N <= 1998:
    print('ABD')
else:
    print('間違っています')

Solution (Python):




N = int(input())

if 1 <= N <=999:
    print('ABC')

else:
    print('ABD')

Solution (Python):
if int(input()) < 1000:
    print('ABC')
else:
    print('ABD')

Solution (Python):
if int(input()) // (999 + 1) == 0:
    print('ABC')
else:
    print('ABD')

Solution (Python):
N = int(input())

if N < 1000:
    print('ABC')

elif 1000 <= N <= 1998:
    print('ABD')

Solution (Python):



n = int(input())


if n < 1000:
    print("ABC")
else:
    print("ABD")

Solution (Python):
contest_num = int(input())

if contest_num >= 1999: 
    result_str = 'The contest has not been held'

elif contest_num < 1000:
    result_str = 'ABC'

elif contest_num >= 1000:
    result_str = 'ABD'

print(result_str)

Solution (Python):





N = int(input())

if N < 1000:
    print('ABC')
else:
    print('ABD')

Solution (Python):
N = int(input())

if N <= 999:
    print("ABC")
else:
    print("ABD")

Solution (Python):



N = int(input())

if 1 <= N & N <= 999:
    print('ABC')
elif 1000 <= N & N <= 1998:
    print('ABD')

Solution (Python):
N= int( input())
if N <= 999:
    print('ABC')

else:
    print('ABD')

Solution (Python):
if int(input()) <= 999:
	print('ABC')
else:
	print('ABD')

Solution (Python):
print('ABC' if int(input()) <= 999 else 'ABD')

Solution (Python):
print('ABC' if int(input()) <=999 else 'ABD')

Solution (Python):



N = int(input()) 


if N < 1 or N > 1998:
    answer = '値が制約外です'
elif N <= 999:
    answer = 'ABC'
else:
    answer = 'ABD'


print(answer)

Solution (Python):

N = int(input())

if N < 1000:
    Contest = "ABC"
    print(Contest)
elif N >= 1000:
    Contest = "ABD"
    print(Contest)

Solution (Python):
S: str = input()
print_list = ['C', 'D']
value = 1000 - int(S)
if value > 0:
    print("AB" + print_list[0])
else:
    print("AB" + print_list[1])

Solution (Python):









input_n = int(input())


reslut_str = 'ABC'
if input_n > 1999:
    result_str = 'The contest has not been held'
else:
    if input_n < 1000:
        reslut_str = 'ABC'
    elif input_n >= 1000:
        reslut_str = 'ABD'

print(reslut_str)

Solution (Python):

taikai_num = int(input())

if taikai_num <= 999:
    print("ABC")
else:
    print("ABD")

Solution (Python):





n = int(input())


if n < 1000:
    print("ABC")
elif n >= 1000:
    print("ABD")

Solution (Python):
a=int(input())
if a>=1000:
    print('ABD')
else:
    print('ABC')

Solution (Python):
n = input()
if len(n) <= 3:
    print('ABC')
else:
    print('ABD')

Solution (Python):
N = int(input())

if 1 <= N <= 999:
    print('ABC')
elif 1000 <= N <= 1998:
    print('ABD')
else:
    print('1以上 1998以下 の値を入力してください')

Solution (Python):




N =int(input(''))
if  1<=N and N<=999:
    print('ABC')
else:
    print('ABD')

Solution (Python):


N = int(input())    

if N < 1000:
    print('ABC')
else:
    print('ABD')

Solution (Python):
N = int(input())

if N >= 1000:
    print('ABD')
else:
    print('ABC')

Solution (Python):
N=int(input())
if N>=1000:
    print('ABD')
else:
    print('ABC')

Solution (Python):
n = int(input())
print('ABC') if n <= 999 else print('ABD')

Solution (Python):
N = int(input())
if N >= 1000:
    print("ABD")
else:
    print("ABC")

Solution (Python):
n = int(input())
if n < 1000:
    x = 'ABC'
else:
    x = 'ABD'
print(x)

Solution (Python):

N = int(input(''))


if N <= 999:
    print('ABC')
elif N >= 1000:
    print('ABD')
else:
    print('Error')

Solution (Python):
N = int(input())

if N < 1000:
    print("ABC")
else:
    print("ABD")

Solution (Python):
N = int(input())
if(N<= 999):
    print('ABC')
else:
    print('ABD')

Solution (Python):
n = int(input())

if n >= 1000:
    print("ABD")
    
if n <= 999:
    print("ABC")

Solution (Python):
n = int(input())

if n >= 1000:
    print("ABD")
else:
    print("ABC")

Solution (Python):
N = int(input())
print('ABD' if N >= 1000 else 'ABC' )

Solution (Python):
n = int(input())
if n<=999:
    print("ABC")
else:
    print("ABD")

Solution (Python):
n=int(input())

if n<=999:
    print('ABC')

else:
    print('ABD')

Solution (Python):
n=int(input())
if n<=999:
    print("ABC")
else:
    print("ABD")

Solution (Python):
n = int(input())
if 1 <= n <= 999:
    print('ABC')
else:
    print('ABD')

Solution (Python):
N = int(input())

if 999>=N>=1:
     print('ABC')
else:
    print('ABD')

Solution (Python):
N = int(input())

if 999>=N>=1:
    print("ABC")
else:
    print("ABD")

Solution (Python):
n = int(input())

if n < 1000:
    print("ABC")
else:
    print("ABD")

Solution (Python):
n=int(input())
print('ABC' if n<1000 else 'ABD')

Solution (Python):







N = int(input())



if N <= 999:
    answer = 'ABC'
elif N <= 1998:
    answer = 'ABD'


print(answer)

Solution (Python):


N = int(input())

if N < 1000:
    print('ABC')
else:
    print('ABD')

Solution (Python):
N = int(input())

if 1 <= N <= 999:
    print('ABC')

else:
    print('ABD')

Solution (Python):
contest_num = int(input())

if contest_num <= 999:
    print('ABC')
elif contest_num >= 1000:
    print('ABD')

Solution (Python):
name = int(input())

if name <= 999:
    print('ABC')
else:
    print('ABD')

Solution (Python):


N = int(input())


if N < 1000:
    print('ABC')
elif 1000 <= N <= 1998:
    print('ABD')
else:
    print('IDK')

Solution (Python):


N = int(input())


if N < 1000:
    print('ABC')
elif 1000 <= N <= 1998:
    print('ABD')

Solution (Python):
N=int(input())
if 1<=N and N<=999:
    print('ABC')
else:
    print('ABD')

Solution (Python):
N = int(input())
if N >= 1000:
    print('ABD')
else :
    print('ABC')

Solution (Python):
n=int(input())

if n<=999:
    print('ABC')
else:
    print('ABD')

Solution (Python):
n = int(input())
print("ABC" if n < 1000 else "ABD")

Solution (Python):
n = int(input())

if n<=999:
  print('ABC')
else:
  print('ABD')

Solution (Python):
N=int(input())
if N<1000:
    ans="ABC"
else:
    ans="ABD"
print(ans)

Solution (Python):
print('ABC' if int(input()) < 1000 else 'ABD')

Solution (Python):
N=int(input())
if N<1000:
  print("ABC")
else:
  print("ABD")

Solution (Python):
n=int(input())
print('ABC' if n<1000 else 'ABD')

Solution (Python):
n = int(input())
if n >= 1000:
  print('ABD')
else:
  print('ABC')

Solution (Python):
a = int(input())
if a <= 999:
  print("ABC")
else:
  print("ABD")

Solution (Python):
n = int(input())
if n <= 999:
  print("ABC")
else:
  print("ABD")

Solution (Python):


n = int(input())

if n <= 999:
    print("ABC")
else:
    print("ABD")

Solution (Python):
n = int (input ())
if n < 1000:
  print ('ABC')
else:
  print ('ABD')

Solution (Python):
print(["ABD","ABC"][len(input())<4])

Solution (Python):
N=int(input())
if N<=999 :
  print("ABC")
else :
  print("ABD")

Solution (Python):
print('ABC' if int(input()) <= 999 else 'ABD')

Solution (Python):
n=int(input())
if n<=999:
  print("ABC")
else:
  print("ABD")

Solution (Python):
n = int(input())
if n<1000:
    print('ABC')
else:
    print('ABD')

Solution (Python):
n = int(input())
if n >= 1000:
    print('ABD')
else:
    print('ABC')

Solution (Python):
n=int(input())
if n<1000:
  print("ABC")
else:
  print("ABD")

Solution (Python):
print('ABC' if int(input()) <= 999 else 'ABD')

Solution (Python):
N = int(input())


def main():
    ans = "ABC" if N < 1000 else "ABD"
    print(ans)


if __name__ == "__main__":
    main()

Solution (Python):
N = int(input())
if N <= 999:
    print('ABC')
else:
    print('ABD')

Solution (Python):









n = int(input())

if (n>=1000):
    print("ABD")
else:
    print("ABC")

Solution (Python):
import sys

read = sys.stdin.read
readline = sys.stdin.readline
readlines = sys.stdin.readlines
sys.setrecursionlimit(10 ** 9)
INF = 1 << 60
MOD = 1000000007


def main():
    N = int(readline())

    if N < 1000:
        print('ABC')
    else:
        print('ABD')

    return


if __name__ == '__main__':
    main()

Solution (Python):
if int(input()) >= 1000:
  print('ABD')
else:
  print('ABC')

Solution (Python):
N = int(input())
print("ABC")if N<=999 else print("ABD")

Solution (Python):
def main():
    n = int(input())
    if n >= 1000:
        print('ABD')
    else:
        print('ABC')


if __name__ == "__main__":
    main()

Solution (Python):
n = int(input())
print("ABC" if n <1000 else "ABD")

Solution (Python):
print(['ABC','ABD'][int(input())>=1000])

Solution (Python):
n = int(input())

if n < 1000:
    print('ABC')
else:
    print('ABD')

Solution (Python):
print('AB'+'CD'[int(input())>999])

Solution (Python):

n = int(input())

if n <= 999: print('ABC')
else: print('ABD')

Solution (Python):
n = int(input())

if n <= 999:
    print("ABC")
else:
    print("ABD")

Solution (Python):
if int(input()) >= 1000:
  print("ABD")
else:
  print("ABC")

Solution (Python):
n=int(input())
if n<=999:print("ABC")
else:print("ABD")

Solution (Python):
import sys

read = sys.stdin.read
readline = sys.stdin.buffer.readline
sys.setrecursionlimit(10 ** 8)
INF = float('inf')
MOD = 10 ** 9 + 7


def main():
    N = int(readline())
    contest = N // 1000
    if contest >= 1:
        print('ABD')
    else:
        print('ABC')


if __name__ == '__main__':
    main()

Solution (Python):
N = int(input())

if N < 1000:
    print('ABC')
else:
    print('ABD')

Solution (Python):
n=int(input())
if n<1000:
    print("ABC")
else:
    print("ABD")

Solution (Python):
N=int(input())
if N<1000:
  print("ABC")
else:
  print("ABD")

Solution (Python):
n=int(input())
if n<=999:
    print("ABC")
else:
    print("ABD")

Solution (Python):
N = int(input())
print("ABC" if N < 1000 else "ABD")

Solution (Python):
n=int(input())
print("ABC" if n<=999 else "ABD")

Solution (Python):
s=int(input())
if s<=999:
    print('ABC')
else:
    print('ABD')

Solution (Python):
n = int(input())
if n < 1000:
    print("ABC")
elif n >= 1000:
    print("ABD")

Solution (Python):
n = int(input())
print('ABC') if n <= 999 else print('ABD')

Solution (Python):
N=int(input())
if N >=1000:print('ABD')
else:print('ABC')

Solution (Python):
n = int(input())
if n <= 999:
  print('ABC')
else:
  print('ABD')

Solution (Python):
n = int(input())

if n<1000:
  print('ABC')
else:
  print('ABD')

Solution (Python):


import math

import itertools
from collections import deque
from collections import Counter
import heapq
from fractions  import gcd


n=int(input())
if n<1000:
    print("ABC")
else:
    print("ABD")

Solution (Python):
n = int(input())
if n < 1000:
    print('ABC')
else:
    print('ABD')

Solution (Python):
s=int(input())
if s>999:
  print("ABD")
else:
  print("ABC")

Solution (Python):

















import sys, re
from collections import deque, defaultdict, Counter
from math import ceil, sqrt, hypot, factorial, pi, sin, cos, radians
from itertools import accumulate, permutations, combinations, product
from operator import itemgetter, mul
from copy import deepcopy
from string import ascii_lowercase, ascii_uppercase, digits
from bisect import bisect, bisect_left
from fractions import gcd
from heapq import heappush, heappop
from functools import reduce
import numpy as np
def input(): return sys.stdin.readline().strip()
def INT(): return int(input())
def MAP(): return map(int, input().split())
def LIST(): return list(map(int, input().split()))
def ZIP(n): return zip(*(MAP() for _ in range(n)))
sys.setrecursionlimit(10 ** 9)
INF = float('inf')
mod = 10 ** 9 + 7

N = INT()
if N < 1000:
    print("ABC")
else:
    print("ABD")

Solution (Python):
N = int(input())
print("ABC" if (N < 1000) else "ABD")

Solution (Python):
a = int(input())

if a<1000:
    print("ABC")

else:
    print("ABD")

Solution (Python):
import bisect, collections, copy, heapq, itertools, math, string, sys
input = lambda: sys.stdin.readline().rstrip() 
sys.setrecursionlimit(10**7)
INF = float('inf')
def I(): return int(input())
def F(): return float(input())
def SS(): return input()
def LI(): return [int(x) for x in input().split()]
def LI_(): return [int(x)-1 for x in input().split()]
def LF(): return [float(x) for x in input().split()]
def LSS(): return input().split()

def resolve():
    N = I()

    if N <= 999:
        print('ABC')
    else:
        print('ABD')

if __name__ == '__main__':
    resolve()

Solution (Python):
n = int(input())

if n >= 1000:
    print('ABD')
else:
    print('ABC')

Solution (Python):
print("AB", end="")
print("C") if int(input()) < 1000 else print("D")

Solution (Python):
def main():
    n = int(input())
    if n < 1000:
        print('ABC')
    else:
        print('ABD')
        
if __name__ == "__main__":
    main()

Solution (Python):
N = int(input())
if N >= 1000:
    print('ABD')
else:
    print('ABC')

Solution (Python):
import sys
def I(): return int(sys.stdin.readline().rstrip())

N = I()
print('ABC' if N <= 999 else 'ABD')

Solution (Python):
print("AB"+"CD"[int(input())>999])

Solution (Python):
n = int(input())

if n >= 1000:
    print('ABD')
else:
    print('ABC')

Solution (Python):
import re
import sys
import math
import itertools
import bisect
from copy import copy
from collections import deque,Counter
from decimal import Decimal
import functools
def v(): return input()
def k(): return int(input())
def S(): return input().split()
def I(): return map(int,input().split())
def X(): return list(input())
def L(): return list(input().split())
def l(): return list(map(int,input().split()))
def lcm(a,b): return a*b//math.gcd(a,b)
sys.setrecursionlimit(10 ** 9)
mod = 10**9+7
cnt = 0
ans = 0
inf = float("inf")

x = k()
if x <= 999:
    print("ABC")
else:
    print("ABD")

Solution (Python):
n= int(input())

if n<=999:
  print("ABC")
else:
  print("ABD")

Solution (Python):
n = int(input())
if n < 1000:
    print("ABC")
else:
    print("ABD")

Solution (Python):
N=int(input())
print("ABC" if N<1000 else "ABD")

Solution (Python):
import math
n  = int(input())
print('AB'+chr(ord('C')+math.ceil(n/999)-1))

Solution (Python):
n=int(input())
if n>=1000:
  print('ABD')
else:
  print('ABC')

Solution (Python):
n = int(input())

if n < 1000:
    print("ABC")
else:
    print("ABD")

Solution (Python):
n = int(input())
print("ABC" if n<=999 else "ABD")

Solution (Python):
N = int(input())
if N < 1000:
    print("ABC")
else:
    print("ABD")

Solution (Python):
print(["ABC","ABD"][1000<=int(input())])

Solution (Python):
N = int(input())

if N <= 999:
    print("ABC")
else:
    print("ABD")

Solution (Python):
N = int(input())
if N>999:
    print('ABD')
    exit()
print('ABC')

Solution (Python):
N=int(input())

if N<=999:
	print("ABC")
else:
	print("ABD")

Solution (Python):
n=int(input())
if n<=999:
  print("ABC")
else:
  print("ABD")

Solution (Python):
n = int(input())

if n < 1000:
    print('ABC')
else:
    print('ABD')

Solution (Python):
n = int(input())
if n<=999:
  print("ABC")
else:
  print("ABD")

Solution (Python):
print('ABD' if 999 < int(input()) else 'ABC')

Solution (Python):
n = int(input())
if n <= 999:
    print('ABC')
else:
    print('ABD')

Solution (Python):
N = int(input())

print("ABC") if N//1000!=1 else print("ABD")

Solution (Python):

N = int(input())

if N < 1000:
	print('ABC')
else:
	print('ABD')

Solution (Python):
print('ABD' if int(input())>999 else 'ABC')

Solution (Python):
import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

n = int(readline())
print('ABC' if n <= 999 else 'ABD')

Solution (Python):
a = int(input())
if a < 1000:
    print("ABC")
else:
    print("ABD")

Solution (Python):
n = int(input())
if n > 999:
    print("ABD")
else:
    print("ABC")

Solution (Python):
n = int(input())
if n >= 1000:
    print('ABD')
else:
    print('ABC')

Solution (Python):
N = int(input())

if N>=1000:
  print('ABD')
else:
  print('ABC')

Solution (Python):
N=int(input())
if 1000<=N:
    print("ABD")
else:
    print("ABC")

Solution (Python):
n = int(input())
if n <= 999:
    print("ABC")
else:
    print("ABD")

Solution (Python):
n = int(input())

if n < 1000:
    print('ABC')
else:
    print('ABD')

Solution (Python):
N=int(input())

if N <=999:
    print("ABC")
else:
    print("ABD")

Solution (Python):
n = int(input())
print("ABC" if n <= 999 else "ABD")

Solution (Python):
a = int(input())
if a<1000:
  print("ABC")
else:
  print("ABD")

Solution (Python):
n = int(input())
if n < 1000:
  print("ABC")
else:
  print("ABD")

Solution (Python):

def main():
  a = int(input())
  if a <= 999:
      print('ABC')
  else:
      print('ABD')
main()

Solution (Python):
import sys, os, math, bisect, itertools, collections, heapq, queue

from decimal import Decimal
from collections import defaultdict, deque

sys.setrecursionlimit(10000000)

ii = lambda: int(sys.stdin.buffer.readline().rstrip())
il = lambda: list(map(int, sys.stdin.buffer.readline().split()))
fl = lambda: list(map(float, sys.stdin.buffer.readline().split()))
iln = lambda n: [int(sys.stdin.buffer.readline().rstrip()) for _ in range(n)]

iss = lambda: sys.stdin.buffer.readline().decode().rstrip()
sl = lambda: list(map(str, sys.stdin.buffer.readline().decode().split()))
isn = lambda n: [sys.stdin.buffer.readline().decode().rstrip() for _ in range(n)]

lcm = lambda x, y: (x * y) // math.gcd(x, y)

MOD = 10 ** 9 + 7
MAX = float('inf')


def main():
    if os.getenv("LOCAL"):
        sys.stdin = open("input.txt", "r")

    N = ii()
    N -= 1
    N //= 999
    s = ord('C') + N
    print('AB' + chr(s))


if __name__ == '__main__':
    main()

Solution (Python):
print('ABC' if int(input()) <= 999 else 'ABD')

Solution (Python):
def solve():
    N = int(input())
    if N < 1000:
        print('ABC')
    else:
        print('ABD')


if __name__ == "__main__":
    solve()