WORST_CASE(?,O(n^1))
* Step 1: NaturalPI WORST_CASE(?,O(n^1))
    + Considered Problem:
        - Strict TRS:
            a__b() -> a()
            a__b() -> b()
            a__f(X1,X2,X3) -> f(X1,X2,X3)
            a__f(a(),X,X) -> a__f(X,a__b(),b())
            mark(a()) -> a()
            mark(b()) -> a__b()
            mark(f(X1,X2,X3)) -> a__f(X1,mark(X2),X3)
        - Signature:
            {a__b/0,a__f/3,mark/1} / {a/0,b/0,f/3}
        - Obligation:
            innermost runtime complexity wrt. defined symbols {a__b,a__f,mark} and constructors {a,b,f}
    + 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) = {2}
        
        Following symbols are considered usable:
          {a__b,a__f,mark}
        TcT has computed the following interpretation:
             p(a) = 1                   
          p(a__b) = 2                   
          p(a__f) = 8 + 8*x1 + x2 + 8*x3
             p(b) = 0                   
             p(f) = 2 + x1 + x2 + x3    
          p(mark) = 10 + 8*x1           
        
        Following rules are strictly oriented:
                   a__b() = 2                      
                          > 1                      
                          = a()                    
        
                   a__b() = 2                      
                          > 0                      
                          = b()                    
        
           a__f(X1,X2,X3) = 8 + 8*X1 + X2 + 8*X3   
                          > 2 + X1 + X2 + X3       
                          = f(X1,X2,X3)            
        
            a__f(a(),X,X) = 16 + 9*X               
                          > 10 + 8*X               
                          = a__f(X,a__b(),b())     
        
                mark(a()) = 18                     
                          > 1                      
                          = a()                    
        
                mark(b()) = 10                     
                          > 2                      
                          = a__b()                 
        
        mark(f(X1,X2,X3)) = 26 + 8*X1 + 8*X2 + 8*X3
                          > 18 + 8*X1 + 8*X2 + 8*X3
                          = a__f(X1,mark(X2),X3)   
        
        
        Following rules are (at-least) weakly oriented:
        

WORST_CASE(?,O(n^1))