View Code of Problem 27

#include<iostream>
using namespace std;
int main() {
	int nums[65536] = { 0 };
	nums[0] = 1;
	nums[1] = 1;
	for (int i = 2; i * i <= 65535; i++)
	{
		if (nums[i] != 1) {
			for (int j = i * i; j <= 65535; j += i)
			{
				nums[j] = 1;
			}
		}
	}
	int a, b;
	while (cin >> a >> b) {
		if (a > b) {
			swap(a, b);
		}
		long long sum = 0;
		for (int i = a+1; i < b; i++)
		{
			if (nums[i] == 0)sum += i;
		}
		cout << sum << endl;
	}
	return 0;
}