View Code of Problem 27

#include<iostream>
#include<math.h>
using namespace std;

int isPrime(int a){
	int b, flag;
	flag = a;
	b = sqrt(a);
	for(int i=2; i<=b; i++){
		if(a % i == 0){
			flag = 0;
			break;
		}
	}
	return flag;
}

int main(){
	int a, b, sum, temp;
	while(cin >> a >> b){
		if(a > b){
			temp = a;
			a = b;
			b = temp;
		}
		sum = 0;
		for(int i=a+1; i<b; i++){
			sum += isPrime(i);
		}
		cout << sum << endl;
	}
}