Output text Yes or No if cell has a, and (b or C) and d in Excel

Cell a1 has letters a, b, c, d, e. I want to output in cell a2 yes or no based on what is identified in cell a1.

I can do: output yes if a, and b, and C are found in a1 by: = IF(AND(ISNUMBER(SEARCH("a",A1)),ISNUMBER(SEARCH("b",A1)),ISNUMBER(SEARCH("c",A1))),"yes","no")

But I cannot do: output yes if a, and (b or C), and D are found in a1...

What formulae modification should I make?