WORST_CASE(?,O(n^1))
* Step 1: NaturalPI WORST_CASE(?,O(n^1))
    + Considered Problem:
        - Strict TRS:
            a__f(X) -> f(X)
            a__f(f(a())) -> a__f(g(f(a())))
            mark(a()) -> a()
            mark(f(X)) -> a__f(mark(X))
            mark(g(X)) -> g(X)
        - Signature:
            {a__f/1,mark/1} / {a/0,f/1,g/1}
        - Obligation:
            innermost runtime complexity wrt. defined symbols {a__f,mark} and constructors {a,f,g}
    + Applied Processor:
        NaturalPI {shape = Linear, restrict = NoRestrict, uargs = UArgs, urules = URules, selector = Nothing}
    + Details:
        We apply a polynomial interpretation of kind constructor-based(linear):
        The following argument positions are considered usable:
          uargs(a__f) = {1}
        
        Following symbols are considered usable:
          {a__f,mark}
        TcT has computed the following interpretation:
             p(a) = 6       
          p(a__f) = 14 + x1 
             p(f) = 10 + x1 
             p(g) = 2       
          p(mark) = 6 + 2*x1
        
        Following rules are strictly oriented:
             a__f(X) = 14 + X         
                     > 10 + X         
                     = f(X)           
        
        a__f(f(a())) = 30             
                     > 16             
                     = a__f(g(f(a())))
        
           mark(a()) = 18             
                     > 6              
                     = a()            
        
          mark(f(X)) = 26 + 2*X       
                     > 20 + 2*X       
                     = a__f(mark(X))  
        
          mark(g(X)) = 10             
                     > 2              
                     = g(X)           
        
        
        Following rules are (at-least) weakly oriented:
        

WORST_CASE(?,O(n^1))