/* -*- coding: utf-8 -*-
 *
 * 3584.cc:  No.3584 Camouflage Mole - yukicoder
 */

#include<cstdio>
#include<algorithm>

using namespace std;

/* constant */

const int MAX_N = 200000;
const int K = 4;
const int MOD = 998244353;

/* typedef */

using ll = long long;

/* global variables */

int dp[MAX_N + 1][K + 1];

/* subroutines */

void addmod(int &a, int b) { a = (a + b) % MOD; }

/* main */

int main() {
  int n;
  scanf("%d", &n);

  dp[0][0] = 1;
  for (int i = 0; i < n; i++) {
    for (int j = 0; j <= K; j++)
      if (dp[i][j]) {
	addmod(dp[i + 1][j], (ll)dp[i][j] * 26 % MOD);
	if (j < K)
	  addmod(dp[i + 1][j + 1], dp[i][j]);
      }
  }

  printf("%d\n", dp[n][K]);

  return 0;
}