View Code of Problem 27

#include <iostream>
using namespace std;
bool isSingle(int a) {
	for (int i = 2; i*i< a+1; i++) {
		if (!(a%i))
			return false;
	}
	return true;
}
void swap(int &a,int &b) {
	int temp = a;
	a = b;
	b = temp;
}
int main() {
	int a, b;
	while (cin>>a>>b) {
		if (a == b) {
			cout << 0 << endl;
			continue;
		}
		if (a > b)
			swap(a, b);
		if (a == 0)
			a++;
		int sum = 0;
		for (int i = a + 1; i < b; i++) {
			if (isSingle(i))
				sum += i;
		}
		cout << sum << endl;
	}
}