From the rules of base pairing, we know that Cytosine always pairs with Guanine and Thymine always pairs with Adenine. These four bases are the only ones used as building blocks of nucleic acids DNA and RNA.
Adenine is abbreviated as A
Thymine is abbreviated as T
Cytosine is abbreviated as C
Guanine is abbreviated as G
There is no base abbreviated as F in nucleic acids so if we omit it, the sequence in the question should read CAGTTACG. The complimenting strand of the DNA molecule would therefore read GTAATGC
