Response : Hai

The basic meaning of hai is "what you have just said is right." It is used in the
answer to a question. Hai also has other usages.

1. It is used when handing something over to someone.

Example
Lwin : Sakanafuraiteeishoku o onegai shimasu.
"I'll have sakanafuraiteeshoku."
Cashier : 350 en itadakimasu.
"350 yen, please."
Lwin : Hai.
"Here you are."
Cashier : Arigatoo gozaimashita.
"Thank you very much."

2. It is used to indicate that the hearer expects the speaker to continue to talk.

Examples
Alice : Sumimasen.
"Excuse me."
Kuno : Hai.
"Yes."
Lwin : Shitsuree shimasu.
"Excuse me."
Office worker : Hai.
"Yes."
In the above examples, ee cannot be used instead of hai.