YES
* Step 1: UnsatRules YES
    + Considered Problem:
        Rules:
          0. f2(A,B,C) -> f1(A,B,C)     True                   (1,1)
          1. f1(A,B,C) -> f1(1 + A,B,C) [B >= 1 + A]           (?,1)
          2. f1(A,B,C) -> f1(1 + A,A,C) [B >= D && A = B]      (?,1)
          3. f1(A,B,C) -> f300(A,B,D)   [A >= B && A >= 1 + B] (?,1)
          4. f1(A,B,C) -> f300(A,B,D)   [A >= B && B >= 1 + A] (?,1)
        Signature:
          {(f1,3);(f2,3);(f300,3)}
        Flow Graph:
          [0->{1,2,3,4},1->{1,2,3,4},2->{1,2,3,4},3->{},4->{}]
        
    + Applied Processor:
        UnsatRules
    + Details:
        Following transitions have unsatisfiable constraints and are removed:  [4]
* Step 2: UnsatPaths YES
    + Considered Problem:
        Rules:
          0. f2(A,B,C) -> f1(A,B,C)     True                   (1,1)
          1. f1(A,B,C) -> f1(1 + A,B,C) [B >= 1 + A]           (?,1)
          2. f1(A,B,C) -> f1(1 + A,A,C) [B >= D && A = B]      (?,1)
          3. f1(A,B,C) -> f300(A,B,D)   [A >= B && A >= 1 + B] (?,1)
        Signature:
          {(f1,3);(f2,3);(f300,3)}
        Flow Graph:
          [0->{1,2,3},1->{1,2,3},2->{1,2,3},3->{}]
        
    + Applied Processor:
        UnsatPaths
    + Details:
        We remove following edges from the transition graph: [(1,3),(2,1),(2,2)]
* Step 3: FromIts YES
    + Considered Problem:
        Rules:
          0. f2(A,B,C) -> f1(A,B,C)     True                   (1,1)
          1. f1(A,B,C) -> f1(1 + A,B,C) [B >= 1 + A]           (?,1)
          2. f1(A,B,C) -> f1(1 + A,A,C) [B >= D && A = B]      (?,1)
          3. f1(A,B,C) -> f300(A,B,D)   [A >= B && A >= 1 + B] (?,1)
        Signature:
          {(f1,3);(f2,3);(f300,3)}
        Flow Graph:
          [0->{1,2,3},1->{1,2},2->{3},3->{}]
        
    + Applied Processor:
        FromIts
    + Details:
        ()
* Step 4: Decompose YES
    + Considered Problem:
        Rules:
          f2(A,B,C) -> f1(A,B,C)      True
          f1(A,B,C) -> f1(1 + A,B,C)  [B >= 1 + A]
          f1(A,B,C) -> f1(1 + A,A,C)  [B >= D && A = B]
          f1(A,B,C) -> f300(A,B,D)    [A >= B && A >= 1 + B]
        Signature:
          {(f1,3);(f2,3);(f300,3)}
        Rule Graph:
          [0->{1,2,3},1->{1,2},2->{3},3->{}]
    + Applied Processor:
        Decompose NoGreedy
    + Details:
        We construct a looptree:
          P: [0,1,2,3]
          |
          `- p:[1] c: [1]
* Step 5: CloseWith YES
    + Considered Problem:
        (Rules:
          f2(A,B,C) -> f1(A,B,C)      True
          f1(A,B,C) -> f1(1 + A,B,C)  [B >= 1 + A]
          f1(A,B,C) -> f1(1 + A,A,C)  [B >= D && A = B]
          f1(A,B,C) -> f300(A,B,D)    [A >= B && A >= 1 + B]
        Signature:
          {(f1,3);(f2,3);(f300,3)}
        Rule Graph:
          [0->{1,2,3},1->{1,2},2->{3},3->{}]
        ,We construct a looptree:
          P: [0,1,2,3]
          |
          `- p:[1] c: [1])
    + Applied Processor:
        CloseWith True
    + Details:
        ()

YES