* Step 1: Sum WORST_CASE(Omega(n^1),?)
    + Considered Problem:
        - Strict TRS:
            a__f(X) -> a__if(mark(X),c(),f(true()))
            a__f(X) -> f(X)
            a__if(X1,X2,X3) -> if(X1,X2,X3)
            a__if(false(),X,Y) -> mark(Y)
            a__if(true(),X,Y) -> mark(X)
            mark(c()) -> c()
            mark(f(X)) -> a__f(mark(X))
            mark(false()) -> false()
            mark(if(X1,X2,X3)) -> a__if(mark(X1),mark(X2),X3)
            mark(true()) -> true()
        - Signature:
            {a__f/1,a__if/3,mark/1} / {c/0,f/1,false/0,if/3,true/0}
        - Obligation:
            innermost runtime complexity wrt. defined symbols {a__f,a__if,mark} and constructors {c,f,false,if,true}
    + Applied Processor:
        Sum {left = someStrategy, right = someStrategy}
    + Details:
        ()
* Step 2: DecreasingLoops WORST_CASE(Omega(n^1),?)
    + Considered Problem:
        - Strict TRS:
            a__f(X) -> a__if(mark(X),c(),f(true()))
            a__f(X) -> f(X)
            a__if(X1,X2,X3) -> if(X1,X2,X3)
            a__if(false(),X,Y) -> mark(Y)
            a__if(true(),X,Y) -> mark(X)
            mark(c()) -> c()
            mark(f(X)) -> a__f(mark(X))
            mark(false()) -> false()
            mark(if(X1,X2,X3)) -> a__if(mark(X1),mark(X2),X3)
            mark(true()) -> true()
        - Signature:
            {a__f/1,a__if/3,mark/1} / {c/0,f/1,false/0,if/3,true/0}
        - Obligation:
            innermost runtime complexity wrt. defined symbols {a__f,a__if,mark} and constructors {c,f,false,if,true}
    + Applied Processor:
        DecreasingLoops {bound = AnyLoop, narrow = 10}
    + Details:
        The system has following decreasing Loops:
          mark(x){x -> f(x)} =
            mark(f(x)) ->^+ a__f(mark(x))
              = C[mark(x) = mark(x){}]

WORST_CASE(Omega(n^1),?)