#include <iostream>
#include <vector>
#include <set>

int main(void)
{
  long long N;
  std::cin >> N;

  const long long MOD = 998244353;
  
  std::vector<long long> dp(N + 2, 0);
  dp[0] = 1;

  for (int i = 0; i < N; i++)
  {
    auto dp_new = std::vector<long long>(N + 2, 0);
    for (int n = 0; n <= N; n++)
    {
      dp_new[n + 1] += dp[n];
      dp_new[n + 1] %= MOD;
      dp_new[n] += dp[n] * 25;
      dp_new[n] %= MOD;
    }
    dp = dp_new;
  }

  long long ans = 0;
  for (int i = 3; i <= N; i++)
  {
    ans += dp[i] * (i / 3);
    ans %= MOD;
  }

  std::cout << ans << std::endl;
  return 0;
}