I have the data and is formula as below to count the number of A, and i want to count only those A that have the value as date formatted. In this case, the result that i want to get is 7 not 9. Could you please advice what should i add to my formula in order to void counting text?

=SUMPRODUCT(--($D$15:$D$270<>""),--($C$15:$C$270="A"))

A 1-Jan-10
A 2-Jan-10
A 3-Jan-10
B 4-Jan-10
B 5-Jan-10
A OK
A 7-Jan-10
A 8-Jan-10
C 9-Jan-10
A 10-Jan-10
B 11-Jan-10
A 12-Jan-10
D 13-Jan-10
A N/A