You will be given a definition of a task first, then some input of the task.
In this task, you need to replace a letter in the sentence with another given letter.

Sentence: 'a herd of elephants is standing on an open plain'. Replace the letter 's' with 'a' in the sentence.
Output:
a herd of elephanta ia atanding on an open plain
You will be given a definition of a task first, then some input of the task.
In this task, you need to replace a letter in the sentence with another given letter.

Sentence: 'a herd of elephants is standing on an open plain'. Replace the letter 's' with 'a' in the sentence.
Output:
user
a herd of elephanta ia atanding on an open plain
assistant
You will be given a definition of a task first, then some input of the task.
In this task, you need to replace a letter in the sentence with another given letter.

Sentence: 'a herd of elephants is standing on an open plain'. Replace the letter 's' with 'a' in the sentence.
Output:
a herd of elephanta ia atanding on an open plain