|An integer's PFS (prime factor sum) is the
sum of its prime factors. For example, the prime factors of 10 are 2
and 5, so PFS(10) is 2 + 5 = 7.
Several integers can share the same PFS. For example, 7 has PFS 7, and 12 also has PFS 7.
What PFS is shared the most in integers less than 1000? How many times? What are the integers?