 # Even Digits – Google Kick Start Round A, 2018

Following is my first submission, which did not pass.

```T = int(input())

for t in range(T):
isPlus = 1
str_num = input()

i = 0
for i in range(len(str_num)):
if i == len(str_num) - 1:
if int(str_num[i]) % 2:
isPlus = -1
else:
isPlus = -2
break
curr_digit = int(str_num[i])
if curr_digit % 2:
next_digit = int(str_num[i + 1])
if next_digit < 5 or curr_digit == 9:
# minus
isPlus = 0
break

res = 0
digits_left =  len(str_num) - i - 1
current = int(str_num[i:])
if isPlus == 1:
target = int(str(int(str_num[i]) + 1) + '0' * digits_left)
res = target - current
elif isPlus == 0: # minus
target = int(str(int(str_num[i]) - 1) + '8' * digits_left)
res = current - target
elif isPlus == -1: # even originally
res = 1
else:
res = 0

print('Case #{}: {}'.format(t + 1, res))

```

I find the hint to be more complicated than mine, but it provides me a more systematic way to solve this problem.

I still can’t find the reason. Maybe think about it later or will you give me the answer?