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

Example Input: Sentence: 'a man is ordering food from a mobile food truck'. Replace the letter 'r' with 'q' in the sentence.
Example Output: a man is oqdeqing food fqom a mobile food tquck

Example Input: Sentence: 'children trying little hamburgers from a tray at school'. Replace the letter 'y' with 'l' in the sentence.
Example Output: children trling little hamburgers from a tral at school

Example Input: Sentence: 'two young girls are playing in a bed'. Replace the letter 't' with 'b' in the sentence.
Example Output:
bwo young girls are playing in a bed