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

Ex Input:
Sentence: 'a train traveling through a dark tunnel next to green brush.'. Replace the letter 'r' with 'e' in the sentence.

Ex Output:
a teain teaveling theough a daek tunnel next to geeen beush.


Ex Input:
Sentence: 'a man and a child skiing down a mountain on a trail'. Replace the letter 'n' with 'm' in the sentence.

Ex Output:
a mam amd a child skiimg dowm a moumtaim om a trail


Ex Input:
Sentence: 'a nice meal on a plate with a green cloth underneath'. Replace the letter 't' with 'i' in the sentence.

Ex Output:

a nice meal on a plaie wiih a green cloih underneaih