CF1700B Palindromic Numbers

During a daily walk Alina noticed a long number written on the ground. Now Alina wants to find some positive number of same length without leading zeroes, such that the sum of these two numbers is a palindrome. Recall that a number is called a palindrome, if it reads the same right to left and left to right. For example, numbers $ 121, 66, 98989 $ are palindromes, and $ 103, 239, 1241 $ are not palindromes. Alina understands that a valid number always exist. Help her find one!

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In the first test case $ 99 + 32 = 131 $ is a palindrome. Note that another answer is $ 12 $ , because $ 99 + 12 = 111 $ is also a palindrome. In the second test case $ 1023 + 8646 = 9669 $ . In the third test case $ 385 + 604 = 989 $ .