number and its prime factors,
each repeated the proper number of times.
The number must be positive and less than
number is given,
factor reads a stream of numbers from the standard input and factors them.
It exits on any input not a positive integer.
Maximum running time is proportional to
Primes prints the prime numbers ranging from
finish are positive numbers less than
finish is missing,
primes prints without end;
start is missing, it reads the starting number from the