MAYBE
* Step 1: FromIts MAYBE
    + Considered Problem:
        Rules:
          0. f1(A,B)   -> f2(-1 + A,B)     [A >= 1]          (?,1)
          1. f2(A,B)   -> f2(-1 + A,1 + B) [A >= 1]          (?,1)
          2. f999(A,B) -> f1(1,-1 + B)     [B >= 1 && A = 0] (1,1)
          3. f1(A,B)   -> f1(1 + A,-1 + B) [B >= 1]          (?,1)
          4. f2(A,B)   -> f1(1 + A,-1 + B) [B >= 1]          (?,1)
        Signature:
          {(f1,2);(f2,2);(f999,2)}
        Flow Graph:
          [0->{1,4},1->{1,4},2->{0,3},3->{0,3},4->{0,3}]
        
    + Applied Processor:
        FromIts
    + Details:
        ()
* Step 2: AddSinks MAYBE
    + Considered Problem:
        Rules:
          f1(A,B)   -> f2(-1 + A,B)      [A >= 1]
          f2(A,B)   -> f2(-1 + A,1 + B)  [A >= 1]
          f999(A,B) -> f1(1,-1 + B)      [B >= 1 && A = 0]
          f1(A,B)   -> f1(1 + A,-1 + B)  [B >= 1]
          f2(A,B)   -> f1(1 + A,-1 + B)  [B >= 1]
        Signature:
          {(f1,2);(f2,2);(f999,2)}
        Rule Graph:
          [0->{1,4},1->{1,4},2->{0,3},3->{0,3},4->{0,3}]
    + Applied Processor:
        AddSinks
    + Details:
        ()
* Step 3: Failure MAYBE
  + Considered Problem:
      Rules:
        f1(A,B)   -> f2(-1 + A,B)      [A >= 1]
        f2(A,B)   -> f2(-1 + A,1 + B)  [A >= 1]
        f999(A,B) -> f1(1,-1 + B)      [B >= 1 && A = 0]
        f1(A,B)   -> f1(1 + A,-1 + B)  [B >= 1]
        f2(A,B)   -> f1(1 + A,-1 + B)  [B >= 1]
        f2(A,B)   -> exitus616(A,B)    True
        f1(A,B)   -> exitus616(A,B)    True
        f1(A,B)   -> exitus616(A,B)    True
        f2(A,B)   -> exitus616(A,B)    True
      Signature:
        {(exitus616,2);(f1,2);(f2,2);(f999,2)}
      Rule Graph:
        [0->{1,4,5},1->{1,4,8},2->{0,3},3->{0,3,6},4->{0,3,7}]
  + Applied Processor:
      Decompose Greedy
  + Details:
      We construct a looptree:
        P: [0,1,2,3,4,5,6,7,8]
        |
        `- p:[0,3,4,1] c: []
MAYBE