import re
F=open('nptmdtrj1.gro','r')
A=open('Trial2.txt','w')
with open ('nptmdtrj1.gro') as F:
	for x in F:
		line=x.strip()
	#	if line.startswith ("Generated by"):
	#		A.write(x)
		if re.search('OW', line):
				A.write(x)
A.close()
F.close()