For an extended explanation please look at problem-076, it's basically the same.. Yet again we remember already calculated values in an grid. The only difference is now that our y-axis is the prime index (We generate a few primes with an [Sieve of Eratosthenes](https://en.wikipedia.org/wiki/Sieve_of_Eratosthenes)). And once we find a number which count is greater five thousand we abort and print this number. The only mayor difference to problem-076 is that now not every summand is valid. It is possible that you can use `prime[7]` but not `prime[6]`. So we have to look at each possible summand individually. This makes unfortunately the optimization where we remember the sum of all values invalid.