package main

import . "fmt"


func main() {
	var n int
	Scan(&n)
	const Mod = 998244353
	dp := make([]int, n+1)
	dp[0] = 1
	for i := 0; i < n; i++ {
		tmp := make([]int, n+1)
		tmp[0] = dp[0] * 25 % Mod
		for j := 0; j < n; j++ {
			tmp[j+1] = (dp[j] + dp[j+1] * 25 % Mod) % Mod
		}
		tmp[n] = (tmp[n] + dp[n]) % Mod
		dp = tmp
	}
	// Println(dp)
	var ans int
	for i := 3; i <= n; i++ {
		ans = (ans + dp[i] * (i / 3) % Mod) % Mod
	}
	Println(ans)
}