MAYBE
* Step 1: UnsatPaths MAYBE
    + Considered Problem:
        Rules:
          0. f2(A,B,C)   -> f2(A,-1 + B,C)   [19 + -1*B >= 0 && 29 >= A] (?,1)
          1. f2(A,B,C)   -> f300(A,-1 + B,C) [19 + -1*B >= 0 && A >= 30] (?,1)
          2. f300(A,B,C) -> f2(A,B,C)        [19 >= B]                   (?,1)
          3. f300(A,B,C) -> f1(A,B,D)        [B >= 20]                   (?,1)
          4. f3(A,B,C)   -> f300(A,B,C)      True                        (1,1)
        Signature:
          {(f1,3);(f2,3);(f3,3);(f300,3)}
        Flow Graph:
          [0->{0,1},1->{2,3},2->{0,1},3->{},4->{2,3}]
        
    + Applied Processor:
        UnsatPaths
    + Details:
        We remove following edges from the transition graph: [(0,1),(1,3)]
* Step 2: TrivialSCCs MAYBE
    + Considered Problem:
        Rules:
          0. f2(A,B,C)   -> f2(A,-1 + B,C)   [19 + -1*B >= 0 && 29 >= A] (?,1)
          1. f2(A,B,C)   -> f300(A,-1 + B,C) [19 + -1*B >= 0 && A >= 30] (?,1)
          2. f300(A,B,C) -> f2(A,B,C)        [19 >= B]                   (?,1)
          3. f300(A,B,C) -> f1(A,B,D)        [B >= 20]                   (?,1)
          4. f3(A,B,C)   -> f300(A,B,C)      True                        (1,1)
        Signature:
          {(f1,3);(f2,3);(f3,3);(f300,3)}
        Flow Graph:
          [0->{0},1->{2},2->{0,1},3->{},4->{2,3}]
        
    + Applied Processor:
        TrivialSCCs
    + Details:
        All trivial SCCs of the transition graph admit timebound 1.
* Step 3: Failure MAYBE
  + Considered Problem:
      Rules:
        0. f2(A,B,C)   -> f2(A,-1 + B,C)   [19 + -1*B >= 0 && 29 >= A] (?,1)
        1. f2(A,B,C)   -> f300(A,-1 + B,C) [19 + -1*B >= 0 && A >= 30] (?,1)
        2. f300(A,B,C) -> f2(A,B,C)        [19 >= B]                   (?,1)
        3. f300(A,B,C) -> f1(A,B,D)        [B >= 20]                   (1,1)
        4. f3(A,B,C)   -> f300(A,B,C)      True                        (1,1)
      Signature:
        {(f1,3);(f2,3);(f3,3);(f300,3)}
      Flow Graph:
        [0->{0},1->{2},2->{0,1},3->{},4->{2,3}]
      
  + Applied Processor:
      Failing "Open problems left."
  + Details:
      Open problems left.
MAYBE