how many arrangements of the letters SWARMED are possible if A and R must be separated by at least 1 letter.

im night sure if this is a combinations or permutations question.

this is what i did. i found the total combinations if A and R are together which is 5!. A and R can be A and R or R and A so thats 2! so 5!*2! than total ways of arranging the letters are 7! so 7!- 5!*2! is the answer i get. i dont think this is right.