You can enter the following in row 11 of Column A, copy to the right as
far as needed:

=IF(OR(COUNTIF(A1:A10,"A")<1,COUNTIF(A1:A10,"B")< 1,COUNTIF(A1:A10,"C")<1,COUNTIF(A1:A10,"D")<1), "ERROR","OK")

If one of the letters is missing or duplicated, "ERROR" will be
returned, else "OK" will appear in each cell of row 11.

HTH

Bruce


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swatsp0p


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