YES(?,ELEMENTARY)

'epo* (timeout of 60.0 seconds)'
--------------------------------
Answer:           YES(?,ELEMENTARY)
Input Problem:    innermost runtime-complexity with respect to
  Rules:
    {  first(0(), X) -> nil()
     , first(s(X), cons(Y)) -> cons(Y)
     , from(X) -> cons(X)}

Proof Output:    
  Strict Rules in Predicative Notation:
   {  first(0(); X) -> nil()
    , first(s(; X); cons(; Y)) -> cons(; Y)
    , from(; X) -> cons(; X)}
  Safe Mapping:
   safe(first) = {2}, safe(0) = {}, safe(nil) = {}, safe(s) = {1},
   safe(cons) = {1}, safe(from) = {1}
  Argument Permutation:
   mu(first) = [2, 1], mu(from) = [1]
  Precedence:
   from ~ from, from > first, first ~ first