Formula to Tag or Delete Duplicate keeping the Rows with paticular Data

Hello to all,

I'm not the best a complex formula's and need some help

I need a formula to mark files as duplicate while comparing multiple columns. I have attached an example.

I have merged 2 different listings of songs. In column "A" I placed a number 1 to indicate the source. Column "B" is the number of the track. Column "C & D" are Title and Artist information. I need to mark the duplicate files as duplicate in Column "E".

If column "B" and "C" are Equal then mark in column "E" duplicate but only mark the file that doesn't have the "1" in Column A. Then I can sort the duplicates and remove.

In some cases I compare 2 columns and other times I compare 3 columns so I need to understand how the formula works so I can change it if I need to.

Thanks for any and all help.

Chuck