#include <bits/stdc++.h>

using namespace std;

using pii = pair<int, int>;
using ll = long long;
const int N = 2000010, MOD = 998244353, INF = 0x3f3f3f3f;
int n, m, w[N];

ll f[N][5];
void solve() {
	scanf("%d", &n);
	f[0][0] = 1;
	for (int i = 1; i < n + 1; i++) {
		f[i][0] = f[i - 1][0] * 26 % MOD;
		for (int j = 1; j <= 4; j++) f[i][j] = (f[i - 1][j] * 26 + f[i - 1][j - 1]) % MOD;
	}
	printf("%lld\n", f[n][4]);
}

int main() {
	int T = 1;
	// scanf("%d", &T);
	while (T--) solve();
	return 0;
}