#sdpsgssolutions
#Triple Hunting
#Starter Problems 3

# Open the input and output files.
inputFile = open("tripin.txt", "r")
outputFile = open("tripout.txt", "w")

# Read how many numbers there will be
myInput = inputFile.readline()
n = int(myInput)

# Reads the integers
integerposition = 1
tripleList = []
while integerposition <= n:
	myInput = inputFile.readline()
	a = int(myInput)
	if a % 3 == 0: 
		tripleList.append('3')
	else:
		tripleList.append('0')
	integerposition = integerposition + 1

howManyThrees = tripleList.count('3')
	
if howManyThrees == 0:
	outputFile.write('Nothing here!')
else:
	
	outputFile.write(str(howManyThrees)+'\n')

	positions = [i+1 for i,x in enumerate(tripleList) if x == '3']
	for items in positions:
		outputFile.write(str(items)+' ')

# Finally, close the input/output files.
inputFile.close()
outputFile.close()