code: def _find_missing_index(ind, n):
      positions = cupy.arange(ind.size)
      diff = ind != positions
      return cupy.where(
          diff.any(),
          diff.argmax(),
          cupy.asarray(ind.size if ind.size < n else -1),
      )
  
imports: import cupy
  import numpy
  from cupy._core import internal
  from cupy import _util
  from cupyx.scipy.sparse import _base
  from cupyx.scipy.sparse import _coo
  from cupyx.scipy.sparse import _sputils
label_desc: Use image node_id 1 for calling a global function with example usage: _find_missing_index(ind, n) and returns: cupy