They will teach us an old Czech round.
(We used to sing this in grade school.) 
But the second verse went:
But no, 'tis not a young boy's head,
'Tis Ifca's castle there instead.
A-hooya, hooya, hooya-ya,
Swiftly flowing river.
And the explanation (which I never knew before) is here:
https://danaxtell.com/ifca/