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#include <bits/stdc++.h>
using namespace std;
bool isPrime(int n) {
for (int i = 2; i <= n / i; i++)
if (n % i == 0) return false;
return true;
}
int main() {
int n, s = 0;
cin >> n;
for (int i = 4; i <= n; i++)
if (!isPrime(i))s += i;
cout << s << endl;
return 0;
}