YES
* Step 1: UnsatPaths YES
    + Considered Problem:
        Rules:
          0. f8(A,B,C,D)  -> f8(-1 + A,B,C,D)  [A >= 0]     (?,1)
          1. f19(A,B,C,D) -> f19(A,-1 + B,C,D) [B >= 0]     (?,1)
          2. f28(A,B,C,D) -> f28(A,B,-1 + C,D) [C >= 0]     (?,1)
          3. f28(A,B,C,D) -> f36(A,B,C,D)      [0 >= 1 + C] (?,1)
          4. f19(A,B,C,D) -> f28(A,B,999,D)    [0 >= 1 + B] (?,1)
          5. f0(A,B,C,D)  -> f19(A,999,C,1)    True         (1,1)
          6. f8(A,B,C,D)  -> f19(A,999,C,D)    [0 >= 1 + A] (?,1)
        Signature:
          {(f0,4);(f19,4);(f28,4);(f36,4);(f8,4)}
        Flow Graph:
          [0->{0,6},1->{1,4},2->{2,3},3->{},4->{2,3},5->{1,4},6->{1,4}]
        
    + Applied Processor:
        UnsatPaths
    + Details:
        We remove following edges from the transition graph: [(4,3),(5,4),(6,4)]
* Step 2: UnreachableRules YES
    + Considered Problem:
        Rules:
          0. f8(A,B,C,D)  -> f8(-1 + A,B,C,D)  [A >= 0]     (?,1)
          1. f19(A,B,C,D) -> f19(A,-1 + B,C,D) [B >= 0]     (?,1)
          2. f28(A,B,C,D) -> f28(A,B,-1 + C,D) [C >= 0]     (?,1)
          3. f28(A,B,C,D) -> f36(A,B,C,D)      [0 >= 1 + C] (?,1)
          4. f19(A,B,C,D) -> f28(A,B,999,D)    [0 >= 1 + B] (?,1)
          5. f0(A,B,C,D)  -> f19(A,999,C,1)    True         (1,1)
          6. f8(A,B,C,D)  -> f19(A,999,C,D)    [0 >= 1 + A] (?,1)
        Signature:
          {(f0,4);(f19,4);(f28,4);(f36,4);(f8,4)}
        Flow Graph:
          [0->{0,6},1->{1,4},2->{2,3},3->{},4->{2},5->{1},6->{1}]
        
    + Applied Processor:
        UnreachableRules
    + Details:
        Following transitions are not reachable from the starting states and are revomed: [0,6]
* Step 3: FromIts YES
    + Considered Problem:
        Rules:
          1. f19(A,B,C,D) -> f19(A,-1 + B,C,D) [B >= 0]     (?,1)
          2. f28(A,B,C,D) -> f28(A,B,-1 + C,D) [C >= 0]     (?,1)
          3. f28(A,B,C,D) -> f36(A,B,C,D)      [0 >= 1 + C] (?,1)
          4. f19(A,B,C,D) -> f28(A,B,999,D)    [0 >= 1 + B] (?,1)
          5. f0(A,B,C,D)  -> f19(A,999,C,1)    True         (1,1)
        Signature:
          {(f0,4);(f19,4);(f28,4);(f36,4);(f8,4)}
        Flow Graph:
          [1->{1,4},2->{2,3},3->{},4->{2},5->{1}]
        
    + Applied Processor:
        FromIts
    + Details:
        ()
* Step 4: Decompose YES
    + Considered Problem:
        Rules:
          f19(A,B,C,D) -> f19(A,-1 + B,C,D)  [B >= 0]
          f28(A,B,C,D) -> f28(A,B,-1 + C,D)  [C >= 0]
          f28(A,B,C,D) -> f36(A,B,C,D)       [0 >= 1 + C]
          f19(A,B,C,D) -> f28(A,B,999,D)     [0 >= 1 + B]
          f0(A,B,C,D)  -> f19(A,999,C,1)     True
        Signature:
          {(f0,4);(f19,4);(f28,4);(f36,4);(f8,4)}
        Rule Graph:
          [1->{1,4},2->{2,3},3->{},4->{2},5->{1}]
    + Applied Processor:
        Decompose NoGreedy
    + Details:
        We construct a looptree:
          P: [1,2,3,4,5]
          |
          +- p:[1] c: [1]
          |
          `- p:[2] c: [2]
* Step 5: CloseWith YES
    + Considered Problem:
        (Rules:
          f19(A,B,C,D) -> f19(A,-1 + B,C,D)  [B >= 0]
          f28(A,B,C,D) -> f28(A,B,-1 + C,D)  [C >= 0]
          f28(A,B,C,D) -> f36(A,B,C,D)       [0 >= 1 + C]
          f19(A,B,C,D) -> f28(A,B,999,D)     [0 >= 1 + B]
          f0(A,B,C,D)  -> f19(A,999,C,1)     True
        Signature:
          {(f0,4);(f19,4);(f28,4);(f36,4);(f8,4)}
        Rule Graph:
          [1->{1,4},2->{2,3},3->{},4->{2},5->{1}]
        ,We construct a looptree:
          P: [1,2,3,4,5]
          |
          +- p:[1] c: [1]
          |
          `- p:[2] c: [2])
    + Applied Processor:
        CloseWith True
    + Details:
        ()

YES