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

Ex Input:
Sentence: 'a crowd watches as giraffes graze the tree tops at the zoo'. Replace the letter 't' with 'q' in the sentence.

Ex Output:
a crowd waqches as giraffes graze qhe qree qops aq qhe zoo

Ex Input:
Sentence: 'a man walking a horse on a dirt track'. Replace the letter 't' with 's' in the sentence.

Ex Output:
a man walking a horse on a dirs srack

Ex Input:
Sentence: 'there is a dog sitting inside this pick up truck'. Replace the letter 'i' with 'x' in the sentence.

Ex Output:
there xs a dog sxttxng xnsxde thxs pxck up truck