What is the answer of write a program which read no N and then generate 54321012345?

To generate the sequence "54321012345" based on an input number ( N ), you can write a simple program that first counts down from ( N ) to 0, then counts back up to ( N ). Here's a Python example:

<code class="language-python">N = int(input("Enter a number: "))
result = ''.join(str(i) for i in range(N, -1, -1)) + ''.join(str(i) for i in range(1, N + 1)) print(result)
</code>

When you input ( N = 5 ), this program will output "54321012345".