print("Problem 1:\n\n")
lbf = float(input("Enter the force measured in lbf: "))
print("The force in Newton is {:6.3f} N.".format(lbf*0.138254954376))


print("\n\n\n\nProblem 2a:\n")
accu = 0
for i in range(1,12):
    accu += i*(i+2)/(i+1)**2
print("The sum is {:6.3f}.".format(accu))

print("\n\n\n\nProblem 2b:\n")
accu = 1
for i in range(1,11):
    accu *= 1-i/(i+10)
print("The product is {:9.6f}.".format(accu))

def guk2gus(uk):
    return uk*0.83267

def rm_punc(string):
    result = [ ]
    for letter in string:
        if letter in ",.:!?":
            result.append("*")
        else:
            result.append(letter)
    return "".join(result)

def lessfour(filename):
    with open(filename) as infile:
        for line in infile:
            words = line.split()
            if len(words)<=3:  #There are three or fewer words in the line
                print(line.strip())