Q: How many strings with seven or more characters can be formed from the letters in EVERGREEN?

What am I suppose to do for this question? Since it asks for "seven or more", am i suppose to add up all the different possibilities?

My answer

im not sure if its right)

[ (7!/(2!2!)) + (7!/(4!)) + (7!/(3!)) ]- For this i took out 2 E's, then 2 R's, then E and R

+

[ (8!/(3!2!)) + (8!/(4!)) ]- For this i took out 1 E, then 1 R.

+

[ 9!/(4!2!)

Is that the correct answer? If not please correct me.

Thanks

Creative