Two constructions are used in English language:
2. of + noun
The construction noun + ‘s is used of nouns denoting living beings, time and in some other cases.
But the construction of + noun can also be used in all these cases – excepting some set phrases – as well as with nouns denoting inanimate objects and adjectives used in the function of a noun in the plural.
|Five miles run.||A run of five miles.|
|The sun’s light.||The light of the sun.|
|The bird’s song.||A song of the bird.|
When persons are concerned, the construction noun + s is preferred.