Neee help with Python code with best performance

given a string S consisting of N characters, returns the alphabetically smallest string that can be obtained by removing exactly one letter from S$.$

Examples:

$1.$ Given S $=$ acb", by removing one letter, you can obtain $"$ac$","$ab$"$ or $"$cb$".$ Your function should return ab$"($after removing $\text{'}$c$\text{'})$ since is alphabetically smaller than $"$ac$"$ and $"$bc$".$

$2.$ Given S$=$ U "hot", your function should return $"$ho$",$ which is alphabetically smaller than $"$ht$"$ and $"$ot$".3.$ Given S $=$ "codility", your function should return "cdility", which can be obtained by removing the second letter.

Given S $=$ "aaaa' your function should return "aaa". Any occurrence of $\text{'}$a$\text{'}$ can be removed. $4.$

Write an efficient algorithm for the following assumptions:

$.$ Nis an integer within the range $[2.\mathrm{.}100,000)$; $$ string S is made only of lowercase letters $($a$-$z$).$