Buggy python submission (verdict: Runtime Error):
a, b = map(int, input().split())

difference = b - a
rtn = sum(range(1, difference + 1))
print(rtn - b)

Fixed submission:
# -*- coding: utf-8 -*-
def margin0(n):
    if n < 10:
        return "00{}".format(n)
    elif n < 100:
        return "0{}".format(n)
    elif n < 1000:
        return "".format(n%1000)
    else:
        return "{}".format(n%1000 - 1)
n = int(input())
# print(n)
name = ""
if n < 1000:
    name = "ABC{}".format(margin0(n))
else:
    name = "ABD{}".format(margin0(n))
print(name[:3])

Buggy python submission (verdict: Runtime Error):
a, b = map(int, input().split())

difference_a_b = b - a
rtn = 0
for i in range(difference_a_b):
    rtn += i+1
print(rtn - b)

Fixed submission:
# -*- coding: utf-8 -*-
def margin0(n):
    if n < 10:
        return "00{}".format(n)
    elif n < 100:
        return "0{}".format(n)
    elif n < 1000:
        return "".format(n%1000)
    else:
        return "{}".format(n%1000 - 1)
n = int(input())
# print(n)
name = ""
if n < 1000:
    name = "ABC{}".format(margin0(n))
else:
    name = "ABD{}".format(margin0(n))
print(name[:3])

Buggy python submission (verdict: Runtime Error):
def poll_height(n):
    rtn = 0 
    for i in range(n + 1): 
        rtn += i
    return rtn 

a, b = map(int, input().split())

difference_a_b = b - a 
print(poll_height(difference_a_b) - b)

Fixed submission:
# -*- coding: utf-8 -*-
def margin0(n):
    if n < 10:
        return "00{}".format(n)
    elif n < 100:
        return "0{}".format(n)
    elif n < 1000:
        return "".format(n%1000)
    else:
        return "{}".format(n%1000 - 1)
n = int(input())
# print(n)
name = ""
if n < 1000:
    name = "ABC{}".format(margin0(n))
else:
    name = "ABD{}".format(margin0(n))
print(name[:3])

Buggy python submission (verdict: Runtime Error):
#def poll_height(n):
#    if n:
#        return n + poll_height(n - 1)
#    else:
#        return 1 

def poll_height(n):
    rtn = 0 
    for i in range(n + 1): 
        rtn += i
    return rtn 

a, b = map(int, input().split())

difference_a_b = b - a 
print(poll_height(difference_a_b) - b)

Fixed submission:
# -*- coding: utf-8 -*-
def margin0(n):
    if n < 10:
        return "00{}".format(n)
    elif n < 100:
        return "0{}".format(n)
    elif n < 1000:
        return "".format(n%1000)
    else:
        return "{}".format(n%1000 - 1)
n = int(input())
# print(n)
name = ""
if n < 1000:
    name = "ABC{}".format(margin0(n))
else:
    name = "ABD{}".format(margin0(n))
print(name[:3])

Buggy python submission (verdict: Runtime Error):
import sys
sys.setrecursionlimit(10000)

def poll_height(n):
    if n:
        return n + poll_height(n - 1)
    else:
        return 1

a, b = map(int, input().split())

difference_a_b = b - a
print(poll_height(difference_a_b) - b)

Fixed submission:
# -*- coding: utf-8 -*-
def margin0(n):
    if n < 10:
        return "00{}".format(n)
    elif n < 100:
        return "0{}".format(n)
    elif n < 1000:
        return "".format(n%1000)
    else:
        return "{}".format(n%1000 - 1)
n = int(input())
# print(n)
name = ""
if n < 1000:
    name = "ABC{}".format(margin0(n))
else:
    name = "ABD{}".format(margin0(n))
print(name[:3])

Buggy python submission (verdict: Runtime Error):
# -*- coding: utf-8 -*-
def margin0(n):
    if n < 10:
        return "00{}".format(n)
    elif n < 100:
        return "0{}".fomrat(n)
    elif n < 1000:
        return "".format(n%1000)
    else:
        return "{}".format(n%1000 - 1)
n = int(input())
# print(n)
name = ""
if n < 1000:
    name = "ABC{}".format(margin0(n))
else:
    name = "ABD{}".format(margin0(n))
print(name[:3])

Fixed submission:
# -*- coding: utf-8 -*-
def margin0(n):
    if n < 10:
        return "00{}".format(n)
    elif n < 100:
        return "0{}".format(n)
    elif n < 1000:
        return "".format(n%1000)
    else:
        return "{}".format(n%1000 - 1)
n = int(input())
# print(n)
name = ""
if n < 1000:
    name = "ABC{}".format(margin0(n))
else:
    name = "ABD{}".format(margin0(n))
print(name[:3])

Buggy python submission (verdict: Runtime Error):
def margin0(n):
    if n < 10:
        return "00{}".format(n)
    elif n < 100:
        return "0{}".fomrat(n)
    elif n < 1000:
        return "".format(n%1000)
    else:
        return "{}".format(n%1000 - 1)
n = int(input())
# print(n)
name = ""
if n < 1000:
    name = "ABC{}".format(margin0(n))
else:
    name = "ABD{}".format(margin0(n))
print(name)

Fixed submission:
# -*- coding: utf-8 -*-
def margin0(n):
    if n < 10:
        return "00{}".format(n)
    elif n < 100:
        return "0{}".format(n)
    elif n < 1000:
        return "".format(n%1000)
    else:
        return "{}".format(n%1000 - 1)
n = int(input())
# print(n)
name = ""
if n < 1000:
    name = "ABC{}".format(margin0(n))
else:
    name = "ABD{}".format(margin0(n))
print(name[:3])

Buggy python submission (verdict: Runtime Error):
def margin0(n):
    if n < 10:
        return f"00".format(n)
    elif n < 100:
        return "0{}".fomrat(n)
    elif n < 1000:
        return "".format(n%1000)
    else:
        return "{}".format(n%1000 - 1)
n = int(input())
# print(n)
name = ""
if n < 1000:
    name = "ABC{}".format(margin0(n))
else:
    name = "ABD{}".format(margin0(n))
print(name)

Fixed submission:
# -*- coding: utf-8 -*-
def margin0(n):
    if n < 10:
        return "00{}".format(n)
    elif n < 100:
        return "0{}".format(n)
    elif n < 1000:
        return "".format(n%1000)
    else:
        return "{}".format(n%1000 - 1)
n = int(input())
# print(n)
name = ""
if n < 1000:
    name = "ABC{}".format(margin0(n))
else:
    name = "ABD{}".format(margin0(n))
print(name[:3])