This is an interactive problem.
The jury has a string $$$s$$$ consisting of lowercase Latin letters. The following constraints apply to this string:
There is also a string $$$t$$$, which is initially empty. Then, $$$|s|$$$ steps happen. During the $$$i$$$-th step, the following events occur:
Your task is to ensure that after the $$$|s|$$$-th step, the string $$$t$$$ is a palindrome.
The interactive interaction starts immediately.
During each step, your program will receive one character — the next character of the string $$$s$$$ or "0" (zero) if the string has ended. If the character "0" is received, your program must terminate immediately.
After receiving $$$s_{i}$$$, you must output the positions of the characters to be swapped, that is, two integers $$$l$$$ and $$$r$$$ ($$$1 \le l,r \le i$$$) or, if you do not want to swap characters, then "0 0".
If your program makes an invalid operation, for example, by trying to swap characters from non-existing positions, or the resulting string $$$t$$$ is not a palindrome, the jury program will print one character "X" on a separate line. If your program receives "X" as the response, it should terminate immediately; otherwise, the verdict of your submission will be undefined.
The interactor in this problem is not adaptive, meaning that the string $$$s$$$ does not change during the interaction.
After each output request, do not forget to output a newline and flush the output buffer. Otherwise, you will receive a verdict of "Idleness limit exceeded". To do this, use:
Hack format
For hacks, use the following format.
The first line should contain a single integer $$$|s|$$$ — the length of the string $$$s$$$.
The second line should contain the $$$s$$$ itself ($$$1 \le |s| \le 99, |s| \bmod 2 = 1$$$), consisting of lowercase Latin letters "a" and "b".
a a b 0
0 0 1 2 2 3
a a b a b 0
0 0 2 1 3 2 4 4 4 5