#include <bits/stdc++.h>

using namespace std;

int main() {
    int n;
    cin >> n;
    
    vector<int> primes(0);
    for (int i = 2; i <= n; ++i) {
        bool isPrime = true;
        for (auto j: primes) {
            if (i % j == 0) {
                isPrime = false;
                break;
            }
        }
        if (isPrime)
            primes.push_back(i);
    }
    
    int ans = 0;
    for (auto i: primes) {
        ans += i;
    }
    
    cout << ans << endl;
}