# -*- coding: utf-8 -*-
"""
Created on Wed Jun  2 21:02:44 2021

@author: LENOVO
"""

import csv

with open('BTMA1.gro') as text_file, open('BTMA2.gro', 'w') as revised_file:
    reader = csv.reader(text_file, delimiter=' ')
    writer = csv.writer(revised_file, delimiter=' ', quoting=0)

    for idx, row in enumerate(reader, start=1):
        if idx >= 3:
            row.insert(1, row[1][0])
            row[2] = row[2][1:]
        writer.writerow(row)