code: def sure_number_block(ctx, n):
      """The number of good Rosser blocks needed to apply
      Turing method
      References:
      R. P. Brent, On the Zeros of the Riemann Zeta Function
      in the Critical Strip, Math. Comp. 33 (1979) 1361--1372
      T. Trudgian, Improvements to Turing Method, Math. Comp."""
      if n < 9 * 10**5:
          return 2
      g = ctx.grampoint(n - 100)
      lg = ctx._fp.ln(g)
      brent = 0.0061 * lg**2 + 0.08 * lg
      trudgian = 0.0031 * lg**2 + 0.11 * lg
      N = ctx.ceil(min(brent, trudgian))
      N = int(N)
      return N
  
file_path: catboost/contrib/python/mpmath/py3/mpmath/functions/zetazeros.py
imports: from .functions import defun, defun_wrapped
label_desc: Use image node_id 5 for calling a global function with example usage: sure_number_block(ctx, n) and returns: N, int