So the problem is...

B! C! D! + A! B C! D! +A B C! D! + A! B! C D + A B! C D + A! B! C D! + A B C D! + A B! C D!

The exclamation points represent NOT while the spaces are to make it easier on the eyes, but they still represent AND. When I tried to do this on my own, I started by taking out the different CD combinations that worked, but I keep simplifying the stuff left over in the parentheses after factoring wrong. I am really struggling, but when I simplified the K-Map, my answer was D! ( A + C! ) + B! C

Please help me!