#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using ll = long long;
using mint = atcoder::modint998244353;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n;
    cin >> n;
    array<mint, 5> dp{};
    dp[0] = 1;
    for(int i = 0; i < n; i++){
        dp[4] *= mint::raw(26);
        for(int j = 3; j >= 0; j--){
            dp[j + 1] += dp[j];
            dp[j] *= mint::raw(26);
        }
    }
    cout << dp[4].val() << endl;
}