collatzConjecture

def collatz():
    while True:
        n = input("Enter a positive integer: ")
        try:
            n = int(n)
        except ValueError:
            print("Not an integer.")
            continue
        if not(n > 0):
            print("Not a positive integer.")
            continue
        else:
            unaltered = n
            break

    s = 0
    while n > 1:
        if n % 2 == 0:
            print(int(n), "is EVEN")
            n = n / 2
            s += 1
        else:
            print(int(n), "is ODD")
            n = (3 * n) + 1
            s += 1

    print("\nIt took", s, "steps to get to 4-2-1 from", unaltered)

if __name__ == "__main__":
    collatz()