<human>:  pid determine existence.
<bot>: Here is a Python program to determine existence

import os

def is_pid_existed(pid):
  """
  Determine whether a pid exists.

  Args:
    pid (int): pid to be determined.

  Returns:
    bool: whether the pid exists.

  Examples:
    >>> is_pid_existed(12345)
    True
    >>> is_pid_existed(-1)
    False
  """
  return os.path.exists("/proc/%d" % pid)

# Enter the pid
pid = 12345

# Calling the function
print((is_pid_existed(pid)))

#Example Output
# False

#Remember to inspect code for bugs.