#include<bits/stdc++.h>
//#include<atcoder/all>
//using namespace atcoder;
using namespace std;
using ll = long long;

ll cnt(ll x){
	ll res = 0;
	while(x){
		res += x&1;
		x/=2;
	}
	return res;
}

int main(){
	ll n;
	cin >> n;
	if(cnt(n)==1){
		cout<<n<<endl;
	}
	else{
		for(ll i = 0;;i++){
			if(n>>i&1LL){
				n -= 1LL<<i;
				cout<<n<<endl;
				return 0;
			}
		}
	}

}