Ignoring the joke.

A metric cup is 250 ml.

250 ml = 250 g

Water ~= 18 g/mol ( H 1.008 g/mol, O 16.something g/mol)

250/18 = 13.8 mol

13.8 mol * 610^23 atoms/mol = 8.3310^24 molecules of water

And there are two atoms of H in one molecule of water, so 1.66*10^25 atoms of hydrogen in a glass of water.

That’s a lot