import re
import sys

file = open(sys.argv[1], 'r')

# HERE: variable 'comment' is a pattern for a comment line in FASTA format
comment = re.compile(.....)

line = file.readline()

seq = []
while line:
    line = line.replace('\n', '')

    # HERE: search pattern in line
    m = comment.......
    if m :
        print ''.join(seq)
        seq = []
    else:
        seq.append(line)
        
    line = file.readline()