Acceptable string

Rahul has recently learned to type and log on to the Internet. He immediately entered a chat room and decided to say hello to everybody. Rahul typed the word $s$. It is considered that Rahul managed to say hello if several letters can be deleted from the typed word so that it resulted in the word **"hello"**. For example, if Rahul types the word **"hehwelloho"**, it will be considered that he said