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

Sentence: 'a person that is sitting under an umbrella'. Replace the letter 'a' with 'l' in the sentence.
l person thlt is sitting under ln umbrelll

Sentence: 'traffic congestion with cars and an electric tram'. Replace the letter 'a' with 'k' in the sentence.
trkffic congestion with ckrs knd kn electric trkm

Sentence: 'a policeman driving a motorcycle on the street'. Replace the letter 'm' with 'c' in the sentence.

a policecan driving a cotorcycle on the street