TASK DEFINITION: In this task, you need to replace a letter in the sentence with another given letter.
PROBLEM: Sentence: 'a man on a horse in riding gear looking onward'. Replace the letter 'o' with 'h' in the sentence.

SOLUTION: a man hn a hhrse in riding gear lhhking hnward

PROBLEM: Sentence: 'a crowd stands under a set of lights in the ceiling and one person holds up a cell phone'. Replace the letter 'r' with 'f' in the sentence.

SOLUTION: a cfowd stands undef a set of lights in the ceiling and one pefson holds up a cell phone

PROBLEM: Sentence: 'a solitary zebra standing in the shade beneath a tree'. Replace the letter 'e' with 'g' in the sentence.

SOLUTION:
a solitary zgbra standing in thg shadg bgngath a trgg