P: I cannot determine the two numbers. - the number I have is not the product of two primes

S: I knew that. - the sum I have cannot be the sum of two primes

P: Now I can determine them. - there is only one factorisation such that the sum cannot be the sum of two primes

S: So can I. - there is only one decomposition of my number into a sum such that the sum of a factorisation of their product cannot be the sum of two primes

CB