Amazon Ec2 Instance 5 linked computers

I need 5 computers linked together on amazon Ec2 cloud computer service. I need the computers to search for prime numbers. I need the 5 computers to take the task of looking for primes and report to a single file the prime number they have found and how long it took to find. I need the process to run un-attended for a period of 3 days. When complete I need the file emailed to me. Scripts to find prime numbers exist on the internet, but will have to be altered. to work in a linked parallel cpu world. I do not car which operating system you choose or which scripting method you employ. I need this done in the next two days.