How many grains of sand to make a heap?

There is a huge literature on vagueness: and this can be illustrated by the paradox of the 'heap'.

It goes as follows:

‘If one has something that is not a heap of sand, and one adds a single grain of sand to it, the result is still not a heap of sand . . .

if n grains of sand are not sufficient to make a heap

then n+1 grains aren’t either.’

So it seems that ‘no matter how many grains of sand may be gathered together, they are not sufficient to make a 'heap' of sand.’