#include #include #include #include using namespace std; int main(void) { ios::sync_with_stdio(false); cin.tie(nullptr); long long N, n, ans = 0; int i, j, cnt=0, p; cin >> N; n = pow(N, 1.0 / 2) + 10; vector hurui; vector res; for (i = 0; i < n; i++) { hurui.push_back(1); } for (i = 2; i < n; i++) { if (hurui[i - 1] == 1) { res.push_back(i); cnt += 1; for (j = 2*i; j < n; j += i) { hurui[j - 1] = -1; } } } for (i = 0; i < cnt; i++) { p = 2; while (pow(res[i], p) <= N) { ans += pow(res[i], p); p += 1; } } cout << ans << endl; return 0; }