#define _CRT_SECURE_NO_WARNINGS	
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
//#define endl '\n'
#define boostIO() ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
ll gcd(ll a, ll b) { return (b == 0 ? a : gcd(b, a % b)); }

ll mod = 998244353;

ll binpow(ll a, ll n) {
	ll res = 1;
	while (n) {
		if (n & 1)
			res = (1LL * res * a) % mod;
		a = (1LL * a * a) % mod;

		n >>= 1;
	}
	return res;
}

signed main() {
	int q = 1;
	//cin >> q;
	while (q--) {
		int n;
		cin >> n;
		vector<ll> dp(n + 3, 0);
		dp[1] = 1, dp[2] = 1;
		for (int i = 3; i <= n; ++i) {
			dp[i] = dp[i - 1] + dp[i - 2];
			if (dp[i] >= mod) dp[i] -= mod;
		}
		cout << (dp[n] * binpow(binpow(2, n), mod - 2)) % mod;
	}
}
