P8553 Awakening

“Where did the fireworks we once envied go? The friends we trusted have drifted away. What did I insist on when I was young? Do you still remember?” Thinking back to what we looked like as children, we are already very different from who we are now; but thinking about ourselves yesterday, there seems to be little difference from today. These unintentional changes have made us into someone else.

Herta uses a sequence $a$ of length $r-l+1$ to describe how her personality has changed. But Herta has a poor memory: she can no longer remember $a$, and only remembers two non-negative integers $l, r$, where $l

A single line with two non-negative integers $l, r$.

On the first line, output `Yes` if there is a solution, otherwise output `No`. Case does not matter. If you output `Yes`, you may output your construction in one of the following two formats: 1. Output one line with $r-l+1$ numbers, representing the permutation you constructed. 3. First output one number, representing the first number of your permutation. Then output a string of length $r-l$. For the $i$-th character, if the $i$-th and $(i+1)$-th numbers in your permutation differ by $2^k$, you should output the $(k+1)$-th lowercase English letter, i.e. `(char)('a'+k)`. **Note: If you use Format 1, you may not be able to pass the last two subtasks. If you receive the judging result from UKE, please consider changing the output format of your answer.** --- **[Scoring Method]** This problem uses a **custom checker** to validate your output. If your judgment about whether a solution exists is wrong, you will get no points. If your judgment about existence is correct, you can get $40\%$ of the points; if no solution exists or you provide a correct construction, you can get the remaining $60\%$ of the points.

**[Sample Explanation #1, #2, #3]** Sample outputs #1 and #2 correspond to the same sequence, i.e. $\{ 0, 1, 3, 2, 6, 7, 5, 4 \}$. Both can get $100 \%$ of the score for that test point. Sample output #3 can get $40 \%$ of the score for that test point. ---- **[Constraints]** For all testdata, it is guaranteed that $0\le l