Need help Please

Question

Write, debug, run a program that exchanges the first and last characters in a given string and returns the new string.

Sample Input:
"abcd"
"a"
"xy"
Sample output:
dbca
a
yx

Answer 1

Asking for solution of problem, without  any apparent effort is highly discouraged.
You should try to add more details on what effort did you put in to solve the problem and where do you feel stuck in solving problem.

Answer 2

I am encouraging this type of questions without any effort but i did made the answer so you can use

b = ""
a = input("Enter the string:")

A = list(a)
b = A[-1]
A[-1] = A[0]
A[0] = b
for element in A:
    print(element, end = "")