View Code of Problem 27

#include<iostream>
#include<cmath>
#include<cstring> 
using namespace std;
int arr[65537];
void flag(){
	for(int i=3;i<65536;++i)
	arr[i]=1;
	for(int i=3;i<=65536;++i){
		for(int j=2;j<=sqrt(i);++j){
		if(i%j==0){
		arr[i]=0;
		break;
		}
		}
	}

}
int main(){
	arr[0]=0;
	arr[1]=0;
	arr[2]=1;
	flag();
	int a,b;
	while(scanf("%d%d",&a,&b)!=EOF){
		if(a>b){
		a=a+b;
		b=a-b;
		a=a-b;
		}
		long long sum=0;
		for(int i=a+1;i<b;++i){
			if(arr[i]){
			sum+=i;
			}
		}
		cout<<sum<<endl;
	}
return 0;
}