python/TangDou/KaoShi/合数的和.cpp

#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;
}