How to write the chemical formula of sixty-nine alkanoic acid?

The chemical formula of alkane is CnH(2n+2).

The structural formula of n-alkanes is:

CH3-(CH2)(n-2)-CH3

Or c (n-1) h (2n-1)-CH3.

In which one methyl -CH3 is replaced by carboxyl -COOH to become monocarboxylic acid;

C(n- 1)H(2n- 1)-COOH

Also known as n-alkanoic acid.

When its chemical formula is CnH(2n)O2.

For sixty-nine alkanoic acids, n=69, so its chemical formula is: C69H 138O2.

Or: C68H 137COOH.