if cell a1 is the same as cell a2 next cell

If cell a2 is different than cell a3 then cell f2 get an E1

If cell a2 and a3 are the same then next cell

if cell a3 and a4 are different then cell f3 gets E2

If cell a1 and cell a2 are different then cell f1 gets E

This needs to go all the way to the bottom of the column