TASK DEFINITION: In this task, you need to replace a letter in the sentence with another given letter.
PROBLEM: Sentence: 'a u.s. military helicopter landing or taking off'. Replace the letter 'i' with 'l' in the sentence.

SOLUTION: a u.s. mllltary hellcopter landlng or taklng off

PROBLEM: Sentence: 'a black and white image of a vehicle that is decorated like a dog'. Replace the letter 'a' with 'p' in the sentence.

SOLUTION: p blpck pnd white impge of p vehicle thpt is decorpted like p dog

PROBLEM: Sentence: 'the bus is trying to navigate though the london traffic'. Replace the letter 'a' with 'l' in the sentence.

SOLUTION:
the bus is trying to nlviglte though the london trlffic