#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main () {
    int N;
    cin >> N;
    ll dp[3030][3030];
    ll m = 998244353;
    for (int i = 0; i <= N; i ++) {
        dp[0][i] = (i == 0);
    }
    for (int i = 1; i <= N; i ++) {
        for (int j = 0; j <= N; j ++) {
            dp[i][j] = 0;
        }
        for (int j = 0; j < N; j ++) {
            dp[i][j] += (dp[i - 1][j] * 25) % m;
            dp[i][j] %= m;
            dp[i][j + 1] += dp[i - 1][j];
            dp[i][j + 1] %= m;
        }
    }
    ll ans = 0;
    for (int i = 0; i <= N; i ++) {
        ans += (dp[N][i] * (i / 3)) % m;
        ans %= m;
    }
    cout << ans << endl;
}