A E F H Z V U what comes next

A = letter 1 in alphabet

E = letter 5 (fifth one along from start)

F = letter 6

H = letter 8

then go in reverse:

Z = letter 26

V = letter 22 (or 5th one along from end)

U = letter 21 (next one back)

S = letter 19 (skip one as there was between F and H but going backwards)