In this task, you need to replace a letter in the sentence with another given letter.

Ex Input:
Sentence: 'a geoup of people on bicycles coming down a street'. Replace the letter 'i' with 'x' in the sentence.

Ex Output:
a geoup of people on bxcycles comxng down a street


Ex Input:
Sentence: 'a close up of a grassy beach showing an umbrella and wind board'. Replace the letter 'a' with 'f' in the sentence.

Ex Output:
f close up of f grfssy befch showing fn umbrellf fnd wind bofrd


Ex Input:
Sentence: 'two gariffs standing in a zoo by a tree limb'. Replace the letter 'e' with 'o' in the sentence.

Ex Output:

two gariffs standing in a zoo by a troo limb