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

Sentence: 'a motorcycle sitting on the side of the road by grass'. Replace the letter 'r' with 't' in the sentence.
a mototcycle sitting on the side of the toad by gtass

Sentence: 'a building has a clock on the top of it'. Replace the letter 'l' with 'x' in the sentence.
a buixding has a cxock on the top of it

Sentence: 'a smiling man stands in the dirty playing with a frisbee'. Replace the letter 'a' with 'c' in the sentence.

c smiling mcn stcnds in the dirty plcying with c frisbee