I've seen this product expanded and I suppose I could search for it. Too lazy.
What is product of :
(x - a) (x - b) ........ (x - z) ?
But clearly it has a x26 term and a abcdefghijklmnopqrstuvwxyz term.
What the other terms must look like can be seen by expanding the first four terms:
(x - a) (x - b)(x - c) (x - d) =
x4  +
x3 [-a -b -c -d] +
x2 [ab + ac + ad + bc + bd + cd] +
x1 [-abc -abd -acd -bcd] +