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

Input: Consider Input: Sentence: 'a man is standing on a snowboard, atop a mountain'. Replace the letter 'd' with 'u' in the sentence.

Output: a man is stanuing on a snowboaru, atop a mountain


Input: Consider Input: Sentence: 'a close up of a grassy beach showing an umbrella and wind board'. Replace the letter 'a' with 'f' in the sentence.

Output: f close up of f grfssy befch showing fn umbrellf fnd wind bofrd


Input: Consider Input: Sentence: 'a tennis player runs towards a tennis ball'. Replace the letter 'n' with 'x' in the sentence.


Output: a texxis player ruxs towards a texxis ball