#include <cassert>
#include <cmath>
#include <algorithm>
#include <iostream>
#include <iomanip>
#include <climits>
#include <map>
#include <queue>
#include <set>
#include <cstring>
#include <vector>

using namespace std;
typedef long long ll;

const ll MOD = 998244353;

int main() {
  int N;
  cin >> N;

  ll dp[N + 1];
  memset(dp, 0, sizeof(dp));
  dp[0] = 1;

  for (int i = 0; i < N; ++i) {
    for (int j = N; j >= 0; --j) {
      if (j < N) {
        dp[j + 1] += dp[j];
        dp[j + 1] %= MOD;
      }

      dp[j] *= 25;
      dp[j] %= MOD;
    }
  }

  ll ans = 0;

  for (int i = 0; i <= N; ++i) {
    ll cnt = i / 3;
    // fprintf(stderr, "i: %d, cnt: %lld\n", i, dp[i]);
    ans += cnt * dp[i];
    ans %= MOD;
  }

  cout << ans << endl;

  return 0;
}