#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Created on Thu Oct 15 22:11:20 2020

@author: lewis
"""

from sys import argv

pdbfilename_in = argv[1]
pdbfilename_out = argv[2]

pdbfile_in = open(pdbfilename_in, 'r')
pdbfile_out = open(pdbfilename_out, 'w')

for line in pdbfile_in:
    if line.startswith('ATOM') and (line[21] != 'K' and line[21] != 'J' and line[21] != 'F'):
        continue
    pdbfile_out.write(line)
            
pdbfile_in.close()
pdbfile_out.close()