# Fish number 1
class Proc
  def <<(other)
    -> (*args) { self[other[*args]] }
  end
 
  def ^(n)
    return -> x { x } if n == 0
    return self << (self ^ (n - 1))
  end
end
 
def B(m, n, f)
  return f[n] if m == 0
  return B(m - 1, 1, f) if n == 0
  return B(m - 1, B(m, n - 1, f), f)
end
 
S =
  -> f {
    -> x {
      B(x, x, f)
    }
  }
 
SS =
  -> trio {
    m, f, s = trio
    n = (s ^ f[m])[f][m]
    g = (s ^ f[m])[f]
    s2 = s ^ f[m]
    [n, g, s2]
  }
 
m0 = 3
f0 = -> x { x + 1 }
S0 = S
 
trio = (SS ^ 63).call([m0, f0, S0])
F1 = trio.first
puts F1

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