MAYBE
Time: 0.065517
TRS:
 {  fib 0() -> 0(),
  fib s 0() -> s 0(),
  fib s s x -> +(fib s x, fib x),
  +(x, 0()) -> x,
  +(x, s y) -> s +(x, y)}
 DP:
  DP:
   {fib# s s x -> fib# x,
    fib# s s x -> fib# s x,
    fib# s s x -> +#(fib s x, fib x),
    +#(x, s y) -> +#(x, y)}
  TRS:
  {  fib 0() -> 0(),
   fib s 0() -> s 0(),
   fib s s x -> +(fib s x, fib x),
   +(x, 0()) -> x,
   +(x, s y) -> s +(x, y)}
  UR:
   {  fib 0() -> 0(),
    fib s 0() -> s 0(),
    fib s s x -> +(fib s x, fib x),
    +(x, 0()) -> x,
    +(x, s y) -> s +(x, y),
      a(z, w) -> z,
      a(z, w) -> w}
   EDG:
    {(fib# s s x -> +#(fib s x, fib x), +#(x, s y) -> +#(x, y))
     (+#(x, s y) -> +#(x, y), +#(x, s y) -> +#(x, y))
     (fib# s s x -> fib# s x, fib# s s x -> fib# x)
     (fib# s s x -> fib# s x, fib# s s x -> fib# s x)
     (fib# s s x -> fib# s x, fib# s s x -> +#(fib s x, fib x))
     (fib# s s x -> fib# x, fib# s s x -> fib# x)
     (fib# s s x -> fib# x, fib# s s x -> fib# s x)
     (fib# s s x -> fib# x, fib# s s x -> +#(fib s x, fib x))}
    STATUS:
     arrows: 0.500000
     SCCS (2):
      Scc:
       {fib# s s x -> fib# x,
        fib# s s x -> fib# s x}
      Scc:
       {+#(x, s y) -> +#(x, y)}
      
      SCC (2):
       Strict:
        {fib# s s x -> fib# x,
         fib# s s x -> fib# s x}
       Weak:
       {  fib 0() -> 0(),
        fib s 0() -> s 0(),
        fib s s x -> +(fib s x, fib x),
        +(x, 0()) -> x,
        +(x, s y) -> s +(x, y)}
       Open
      
      SCC (1):
       Strict:
        {+#(x, s y) -> +#(x, y)}
       Weak:
       {  fib 0() -> 0(),
        fib s 0() -> s 0(),
        fib s s x -> +(fib s x, fib x),
        +(x, 0()) -> x,
        +(x, s y) -> s +(x, y)}
       Open