#include "bits/stdc++.h"
using namespace std;

using ll = long long;
using P = pair<ll, ll>;
const ll INF = (1LL << 61);
ll mod = 998244353;

signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	ll N; cin >> N;
	ll now = 1;
	for (int i = 0; i < 60; i++) {
		if (now > N) {
			cout << now / 2 << endl;
			break;
		}
		now *= 2;
	}
	return 0;
}