#include <bits/stdc++.h>
using namespace std;
using ll = long long;
ll C(int a) {
	// a個の中から4つ選ぶ
	ll x = (a*(a-1))%998244353ll;
	ll y = ((a-2ll)*(a-3ll))%998244353ll;
	return x*y/24ll;
}
int main() {
	int a;
	cin >> a;
	ll ans;
	ans = C(a);
	for (int i = 4; i < a; i++) {
		ans *= 26ll;
		ans = (ans%998244353ll);
	}
	cout << ans << endl;
	return 0;
}