# testing all numbers from 1 to upper limit!
# variables are initialised

highestchain=0
count=0                                 # stores integer currently being tested

print ("ODDS AND EVENS")

# user establishes a range for checking
uppernum=int(input("Choose your upper limit:"))


while uppernum>count:
	count+=1                        # count stores integer currently being tested                       
	x=count                         # x holds value while testing each step
	step=1                          # step counts number of links in chain
	while x!=1:                     # loop creates chain
		if x%2==0:
			x=int(x/2)
		else:
			x=int(x*3+1)
		step+=1
	print("The number",count,"has a chain length of",step)
	if step>highestchain:           # highestchain stores the highest length chain currently found
		highestchain=step
		highestint=count
print()
print("All integers up to your upper limit have been tested and the one \nwhich created the longest chain was",highestint,"with a length of",highestchain)

# fix: endless loop printing highest chain