View Code of Problem 27

#include<bits/stdc++.h>
using namespace std;
bool str[65600];
void prime(){
	str[1]=1;
	for(int i=2;i*i<65537;++i){
		if(!str[i]){
			for(int j=i*i;j<=65537;j+=i)
			str[j]=1;
		}
	}
}
int main(){
	prime();
	int n,m;
	while(cin>>n>>m&&n!=EOF){
		long long int ans=0;
		if(n>m)
		swap(n,m);
		for(int i=n+1;i<m;++i){
			if(!str[i]){
				ans+=i;	
			}
		
		}
		cout<<ans<<endl;
	}
}