# coding: utf-8
sample = ['GTA', 'GGG', 'CAC']

def readDNA(dna_file):
	dna_data = ""
	with open(dna_file, "r") as f:
		for line in f:
			dna_data += line
	return dna_data

def dnaCodons(dna):
	codons = []
	for i in range(0, len(dna), 3):
		if (i+3) < len(dna):
			codons.append(dna[i:i+3])
	return codons

def matchDNA(dna):
	matches = 0
	for codon in dna:
		if codon in sample:
			matches += 1
	return matches

def isCriminal(dna_sample):
	dna_data = readDNA(dna_sample)
	codons = dnaCodons(dna_data)
	num_matches = matchDNA(codons)
	if num_matches >= 3:
		print "Matches total: %s" % (str(num_matches))
		print "The investigation should continue."
	else:
		print "Matches total: %s" % (str(num_matches))
		print "The suspect can be set free."

isCriminal('suspect1.txt')
isCriminal('suspect2.txt')
isCriminal('suspect3.txt')