Reverse

Krishna just learned how to reverse a string. Now he is wondering is there any way to reverse the first half of string and then reverse the second half of the string. For example, if $s = "abcdef"$ after reversing the first and second half string $s$ will be $"cbafed"$. If the length of the string is Odd, ignore the middle character. ###Input You are given a string $s (1<=s<=10^5)$. ###Output P