#include<bits/stdc++.h>
#define int long long
#define matsuri pair<int,int>
//const int iris = 1e9+7;
const int iris = 998244353;
using namespace std;

void solve()
{
	int n;
	cin>>n;
	vector<vector<int> > dp(n+1, vector<int>(n+1));
	dp[0][0]=1;
	for(int i=1;i<=n;i++)
	{
		for(int j=0;j<=i;j++)
		{
			dp[i][j]=dp[i-1][j]*25%iris;
			if(j)
				dp[i][j]=(dp[i][j]+dp[i-1][j-1])%iris;
		}
	}
	int ans=0;
	for(int i=0;i<=n;i++)
		ans=(ans+dp[n][i]*(i/3))%iris;
	cout<<ans<<'\n';
}

signed main()
{
	ios::sync_with_stdio(0);
	cin.tie(0);

	int T=1;
	//cin>>T;
	while(T--)
		solve();

	return 0;
}