#include<iostream>
#include<algorithm>
#include<vector>
#include<string>
using namespace std;
int main(){
	int n;
	while(cin >> n,n){
		int count=0;
		int sosu=0;
		for(int i=2;;i++){
			if(count==n)
				break;
			if(i==2){
				sosu+=2;
				count++;
			}
			else{
				for(int j=2;j<i;j++){
					if(i%j==0)
						break;
					if(j==i-1){
						sosu+=i;
						count++;
					}
				}
			}
		}
		cout << sosu << endl;
	}
}