First and last appearance#4726
One string is given.
If the letter '' occurs in the string only once, print its index (indexing starts from ).
If the letter '' occurs two or more times, print the indices of its first and last occurrences.
If the letter '' does not appear in the string, print nothing.
One single string with a length not exceeding characters.
Print the result based on the number of occurrences of the letter '' in the string.
Example 1
Example 2