Ignoring the joke.
A metric cup is 250 ml.
250 ml = 250 g (the density of water is intentionally 1.000 g / ml)
Water ~= 18 g/mol ( H 1.008 g/mol, O 16.something g/mol)
250 g / 18 g/mol = 13.8 mol
13.8 mol * 6 * 10^23 atoms/mol = 8.33 * 10^24 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