YES(?,ELEMENTARY)

'epo* (timeout of 60.0 seconds)'
--------------------------------
Answer:           YES(?,ELEMENTARY)
Input Problem:    innermost runtime-complexity with respect to
  Rules:
    {  a__c() -> a__f(g(c()))
     , a__f(g(X)) -> g(X)
     , mark(c()) -> a__c()
     , mark(f(X)) -> a__f(X)
     , mark(g(X)) -> g(X)
     , a__c() -> c()
     , a__f(X) -> f(X)}

Proof Output:    
  Strict Rules in Predicative Notation:
   {  a__c() -> a__f(; g(; c()))
    , a__f(; g(; X)) -> g(; X)
    , mark(c();) -> a__c()
    , mark(f(; X);) -> a__f(; X)
    , mark(g(; X);) -> g(; X)
    , a__c() -> c()
    , a__f(; X) -> f(; X)}
  Safe Mapping:
   safe(a__c) = {}, safe(a__f) = {1}, safe(g) = {1}, safe(c) = {},
   safe(mark) = {}, safe(f) = {1}
  Argument Permutation:
   mu(a__c) = [], mu(a__f) = [1], mu(mark) = [1]
  Precedence:
   mark ~ mark, mark > a__f, mark > a__c, a__f ~ a__f, a__c > a__f,
   a__c ~ a__c