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

Sentence: 'a small bird perched on a open window'. Replace the letter 'e' with 'r' in the sentence.
a small bird prrchrd on a oprn window

Sentence: 'a yellow fire truck parked in a parking lot'. Replace the letter 'a' with 'y' in the sentence.
y yellow fire truck pyrked in y pyrking lot

Sentence: 'a red and brown bird walking through brush of the same color'. Replace the letter 'i' with 'a' in the sentence.
a red and brown bard walkang through brush of the same color