#!/usr/bin/env python
#
# Tom Venken : 19/02/2016
# 
# Read in index file of sn1 POPC atoms and print out bonds in each POPC
#

filename = "order.ndx"

#read in the file 
with open(filename) as f:
    content = f.read().split()

i=0
j=0

#loop over file content, skip in case the last carbon is found in sn1 (16C's)
for number in content:
    if j != 15:
       print content[i],content[i+1] #,i,j
       i += 1
       j += 1
    else:
       j=0
       i += 1

#    print " %s %s " % (number,number)

#for num in range(0,len(content)):
#     j=num+1
#     print " %s %s" % (num,j)

#print len(content)