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

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

Solution (Python):
import sys, re
from math import ceil, floor, sqrt, pi, factorial, gcd
from copy import deepcopy
from collections import Counter, deque
from heapq import heapify, heappop, heappush
from itertools import accumulate, product, combinations, combinations_with_replacement
from bisect import bisect, bisect_left, bisect_right
from functools import reduce
from decimal import Decimal, getcontext

def i_input(): return int(input())
def i_map(): return map(int, input().split())
def i_list(): return list(i_map())
def i_row(N): return [i_input() for _ in range(N)]
def i_row_list(N): return [i_list() for _ in range(N)]
def s_input(): return input()
def s_map(): return input().split()
def s_list(): return list(s_map())
def s_row(N): return [s_input for _ in range(N)]
def s_row_list(N): return [list(s_input()) for _ in range(N)]
def lcm(a, b): return a * b // gcd(a, b)
sys.setrecursionlimit(10 ** 6)
INF = float('inf')
MOD = 10 ** 9 + 7
num_list = []
str_list = []

def main():
    n = i_input()

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

if __name__ == '__main__':
    main()

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

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

if t<1000:
    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 <= 999:
    print('ABC')
else:
    print('ABD')

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

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

Solution (Python):
import sys
sys.setrecursionlimit(10000000)
MOD = 10 ** 9 + 7
INF = 10 ** 15

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

if __name__ == '__main__':
    main()

Solution (Python):
import sys
import math
import itertools
import collections
import heapq
import re
import numpy as np

rr = lambda: sys.stdin.readline().rstrip()
rs = lambda: sys.stdin.readline().split()
ri = lambda: int(sys.stdin.readline())
rm = lambda: map(int, sys.stdin.readline().split())
rl = lambda: list(map(int, sys.stdin.readline().split()))
inf = float('inf')
mod = 10**9 + 7

print('ABD' if ri() > 999 else 'ABC')

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

if not ( 1 <= N <= 1998 ):
    sys.exit()

print('ABD') if N > 999 else print('ABC')

Solution (Python):
print('DC'[len(input('AB'))<4])

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

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

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

Solution (Python):
N = int(input())
print("ABD" if N>=1000 else "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):
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):
print('ABC'if len(input())<4else'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())
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<=999:
    print('ABC')

elif 999<n:
    print('ABD')

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

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

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

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

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

else:
    print("ABC")

Solution (Python):
import sys
def input(): return sys.stdin.readline().strip()


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


if __name__ == "__main__":
    main()

Solution (Python):


n = int(input())

if (n // 1000) == 0:
    print('ABC')
else:
    print('ABD')

Solution (Python):
print('ABC'*(len(input())<4)or'ABD')

Solution (Python):
import sys
import math
import itertools
import bisect
from copy import copy
from collections import deque,Counter
from decimal import Decimal
def s(): return input()
def i(): return int(input())
def S(): return input().split()
def I(): return map(int,input().split())
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

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

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

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

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

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

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

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):
def main():
    from builtins import int, map, list, print
    import sys
    sys.setrecursionlimit(10 ** 6)

    input = (lambda: (sys.stdin.readline()).rstrip())
    input_list = (lambda: input().split())
    input_number = (lambda: int(input()))
    input_number_list = (lambda: list(map(int, input_list())))

    N = input_number()
    print("AABBCD"[N > 999::2])


if __name__ == '__main__':
    main()

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

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

Solution (Python):
n=int(input())
if n - 999 > 0:
  print('ABD')
else:
  print('ABC')

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

Solution (Python):

N = int(input())


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

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


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 < 1000 else 'ABD')

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

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

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

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

Solution (Python):
N = int(input())
if N >= 1000:
    N += 1
    print('ABD')
else:
    print('ABC')

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

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

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

Solution (Python):
n = int(input())
print ('ABC') if n <= 999 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):
def actual(n):
    if 1 <= n <= 999:
        return 'ABC'

    return 'ABD'

n = int(input())
print(actual(n))

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

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

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

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

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

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

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

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

if __name__ == '__main__':
    main()

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

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

print(ans)

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

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

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

Solution (Python):
N = input()
n = len(N)
ans = 'ABC'
if n > 3:
  ans = 'ABD'
print(ans)

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())
print("ABC" if len(str(n))<=3 else "ABD")

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

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

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

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

Solution (Python):
print("AB"+"CD"[len(input())==4])

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

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

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

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

Solution (Python):

import sys
input = sys.stdin.readline









N = int(input())

i = (N-1) // 999

print("AB" + "CD"[i])

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

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

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

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

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

Solution (Python):

import sys

sr = lambda: sys.stdin.readline().rstrip()
ir = lambda: int(sr())
lr = lambda: list(map(int, sr().split()))

N = ir()
answer = 'ABC' if N < 1000 else 'ABD'
print(answer)

Solution (Python):
n = input()
if len(n) == 4:
  print('ABD')
else:
  print('ABC')

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

Solution (Python):
from sys import stdin

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

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

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

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

if 1 <= 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())

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

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

Solution (Python):
print('ABD' if int(input())>999 else '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 n < 1000:
    ans = "ABC"
else:
    ans = "ABD"
print(ans)

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

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

Solution (Python):
from collections import defaultdict, deque
import sys


def LI(): return list(map(int, sys.stdin.buffer.readline().split()))
def I(): return int(sys.stdin.buffer.readline())
def LS(): return sys.stdin.buffer.readline().rstrip().decode('utf-8').split()
def S(): return sys.stdin.buffer.readline().rstrip().decode('utf-8')
def IR(n): return [I() for i in range(n)]
def LIR(n): return [LI() for i in range(n)]
def SR(n): return [S() for i in range(n)]
def LSR(n): return [LS() for i in range(n)]
def SRL(n): return [list(S()) for i in range(n)]
def MSRL(n): return [[int(j) for j in list(S())] for i in range(n)]


n = I()
if n >= 1000:
    ans = 'ABD'
    if len(str(n - 999)) == 1:
        ans += '00' + str(n - 999)
    elif len(str(n - 999)) == 2:
        ans += '0' + str(n - 999)
    else:
        ans += str(n - 999)

else:
    ans = 'ABC'
    if len(str(n)) == 1:
        ans += '00' + str(n)
    elif len(str(n)) == 2:
        ans += '0' + str(n)
    else:
        ans += str(n)
print(ans[:3])

Solution (Python):
N = int(input())
if N // 1000 == 0:
  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:
    print("ABD")
else:
    print("ABC")

Solution (Python):
n = input()
if len(n) < 4:
  print('ABC')
else:
  print('ABD')

Solution (Python):
from sys import stdin
input = stdin.readline

def VI(N, init=0):
  return [init for _ in range(N)]
def VVI(N, M, init=0):
  return [[init for _ in range(M)] for _ in range(N)]

def VD(N, init=0.0):
  return [init for _ in range(N)]
def VVD(N, M, init=0.0):
  return [[init for _ in range(M)] for _ in range(N)]

def Decimal(x):
  print("{0:.10f}".format(x))

class Pair:
  def __init__(self, x=0, y=0):
    self.first = x
    self.second = y

  def __repr__(self):
    return '{0} {1}'.format(self.first, self.second)

  def __lt__(self, pi):
    return self.first < pi.second

def POW(x, n):
  ret = 1
  while n:
    if n&1:
      ret *= x
    x *= x
    n >>= 1
  return ret

N = int(input().rstrip())
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 / 999 <= 1 else "ABD")

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

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

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):


import sys






























def main():
    mod = 1000000007                
    inf = float('inf')              
    
    sys.setrecursionlimit(10**6)    
    def input(): return sys.stdin.readline().rstrip()
    def ii():    return int(input())
    def mi():    return map(int, input().split())
    def mi_0():  return map(lambda x: int(x)-1, input().split())
    def lmi():   return list(map(int, input().split()))
    def lmi_0(): return list(map(lambda x: int(x)-1, input().split()))
    def li():    return list(input())
    
    
    n = ii()
    print('ABD') if n >= 1000 else print('ABC')


if __name__ == "__main__":
    main()

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

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

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

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

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):
def resolve():
	n = int(input())
	if n > 999:
		print('ABD')
	else:
		print('ABC')
resolve()

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

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

Solution (Python):

print(['ABD', 'ABC'][int(input()) <= 999])

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

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

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

Solution (Python):
n = int(input())
ans = 'AB'
if n <= 999:
  ans += 'C'
else:
  ans += 'D'
print(ans)

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

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

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

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

Solution (Python):
if int(input())>999:
  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<1000:
    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):
if int(input()) <= 999:
  print('ABC')
else:
  print('ABD')

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

Solution (Python):

N = int(input())



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

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

Solution (Python):
def ABC_99_A():
    N = int(input())
    if N < 1000:
        print('ABC')
    else:
        print('ABD')

if __name__ == '__main__':

    ABC_99_A()

Solution (Python):
import sys

input = sys.stdin.readline


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

    if N < 1000:
        ans = "ABC"
    else:
        ans = "ABD"

    print(ans)


if __name__ == "__main__":
    main()

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

Solution (Python):
N=int(input())
print('ABC' if N<1000 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):
def main():
    n = int(input())
    print('ABC' if n<=999 else 'ABD')

if __name__ == '__main__':
    main()

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

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):
l = ["ABC","ABD"]
import math
n = int(input())
print(l[math.floor(n/1000)])

Solution (Python):
import bisect,collections,copy,heapq,itertools,math,string
import sys
def S(): return sys.stdin.readline().rstrip()
def I(): return int(sys.stdin.readline().rstrip())
def LS(): return list(sys.stdin.readline().rstrip().split())
def LI(): return list(map(int,sys.stdin.readline().rstrip().split()))

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

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

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

Solution (Python):

import sys
import math
from bisect import bisect_left, bisect_right, insort_left, insort_right
from collections import defaultdict, deque, Counter
from copy import deepcopy
from fractions import gcd
from functools import lru_cache, reduce
from heapq import heappop, heappush
from itertools import accumulate, groupby, product, permutations, combinations, combinations_with_replacement
from math import ceil, floor, factorial, log, sqrt, sin, cos
from operator import itemgetter
from string import ascii_lowercase, ascii_uppercase, digits
sys.setrecursionlimit(10**7)
rs = lambda: sys.stdin.readline().rstrip()
ri = lambda: int(rs())
rf = lambda: float(rs())
rs_ = lambda: [_ for _ in rs().split()]
ri_ = lambda: [int(_) for _ in rs().split()]
rf_ = lambda: [float(_) for _ in rs().split()]
INF = float('inf')
MOD = 10 ** 9 + 7
PI = math.pi

N = ri()
print('ABC' if N < 1000 else '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 = input()
if len(n)==4:
    print('ABD')
else:
    print('ABC')

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

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

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

Solution (Python):
n = int(input())
print('ABC') if n > 0 and n < 1000 else print('ABD')

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

Solution (Python):

n = int(input())
if n > 999:
    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('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<=999 else "ABD")

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

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

Solution (Python):






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


print(main())

Solution (Python):
n = int(input())
print('ABC' if n < 1000 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):
a=int(input())
if a<=999:
    print("ABC")
else:
    print("ABD")

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())

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):
import sys
import itertools
sys.setrecursionlimit(1000000000)
from heapq import heapify,heappop,heappush,heappushpop

import collections

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

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

Solution (Python):
print("ABC" if int(input())<=999 else "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 <= 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 = input()
if len(n) < 4:
  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>=1000):
    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, groupby
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
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()
print("ABC" if N < 1000 else "ABD")

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

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

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

Solution (Python):

import sys
sys.setrecursionlimit(10**9)
INF=10**18
MOD=10**9+7
input=lambda: sys.stdin.readline().rstrip()
YesNo=lambda b: bool([print('Yes')] if b else print('No'))
YESNO=lambda b: bool([print('YES')] if b else print('NO'))
int1=lambda x:int(x)-1

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("ABD")
else: print("ABC")

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

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

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

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

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

Solution (Python):
def main():
    X = int(input())
    return 'ABD' if X > 999 else 'ABC'

print(main())

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

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

if n <= 3:
  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):
N = int(input())
if N < 1000:
    print('ABC')
else:
    print('ABD')

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

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

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

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