instruction:
In this task, you need to replace a letter in the sentence with another given letter.
question:
Sentence: 'a book shelf full of books and nick nacks '. Replace the letter 'o' with 'm' in the sentence.
answer:
a bmmk shelf full mf bmmks and nick nacks 


question:
Sentence: 'a group of young adults are engaged in outdoor exercise'. Replace the letter 'g' with 'n' in the sentence.
answer:
a nroup of younn adults are ennaned in outdoor exercise


question:
Sentence: 'several surfers are standing in front of their surfboards on a beach'. Replace the letter 'i' with 'c' in the sentence.
answer:

several surfers are standcng cn front of thecr surfboards on a beach