#pragma GCC optimize("O3, unroll-loops, Ofast")
#include<bits/stdc++.h>
using namespace std;
#define pii pair<int,int>
#define tiii tuple<int,int,int>
int mod = 998244353;
vector<vector<int>> pos;
vector<int> cur;
void gen(int n){
    if(n == 0){
        pos.push_back(cur);
        return;
    }
    for(int i = 0; i < 7; i++){
        cur.push_back(i);
        gen(n-1);
        cur.pop_back();
    }   
}
int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    int n;
    cin >> n;
    vector<tiii> arr(n);
    vector<vector<vector<int>>> cnt(8, vector<vector<int>>(26, vector<int>(26)));
    set<string> occ;
    for(int i = 0; i < n; i++){
        string s;
        cin >> s;
        string r = s;
        reverse(r.begin(),r.end());
        arr[i] = {s.size(), s[0]-'a', s.back()-'a'};
        if(occ.count(r)   || occ.count(s)) continue; 
        cnt[s.size()-3][s[0]-'a'][s.back()-'a']++;
    
        if(r != s){
            cnt[s.size()-3][s[0]-'a'][s.back()-'a']++;
        }
    }
    auto start = clock();
    set<pii> edges;
    for(int v = 0; v < 4; v++){
        auto ins = [&](int a, int b){
            if(a > b) swap(a,b);
            edges.insert({a,b});
        };
        ins(v, (v+1)%4);
        ins(v, (v+3)%4);
        ins(v, v+4);
        ins(4+v, 4+((v+1)%4));
        ins(4+v, 4+((v+3)%4));
    }
    
    gen(8);
    int res = 0;
    cerr << pos.size() << endl;
    for(auto corners : pos){
        for(int l = 3; l <= 10; l++){
            int cp = 1;
            for(auto e : edges){
                cp *= cnt[l-3][corners[e.first]][corners[e.second]];
                cp %= mod;
            }
        
            res += cp;
            res %= mod;
        }
    }
    auto end = clock();
    cout << res << endl;
    cerr << end-start << "ms elapsed" << endl;
}
Compilation message (stderr)
cubeword.cpp:1:47: warning: bad option '-f unroll-loops' to pragma 'optimize' [-Wpragmas]
    1 | #pragma GCC optimize("O3, unroll-loops, Ofast")
      |                                               ^
cubeword.cpp:1:47: warning: bad option '-f Ofast' to pragma 'optimize' [-Wpragmas]
cubeword.cpp:12:15: warning: bad option '-f unroll-loops' to attribute 'optimize' [-Wattributes]
   12 | void gen(int n){
      |               ^
cubeword.cpp:12:15: warning: bad option '-f Ofast' to attribute 'optimize' [-Wattributes]
cubeword.cpp:24:10: warning: bad option '-f unroll-loops' to attribute 'optimize' [-Wattributes]
   24 | int main(){
      |          ^
cubeword.cpp:24:10: warning: bad option '-f Ofast' to attribute 'optimize' [-Wattributes]
cubeword.cpp: In function 'int main()':
cubeword.cpp:54:36: warning: bad option '-f unroll-loops' to attribute 'optimize' [-Wattributes]
   54 |         auto ins = [&](int a, int b){
      |                                    ^
cubeword.cpp:54:36: warning: bad option '-f Ofast' to attribute 'optimize' [-Wattributes]| # | Verdict | Execution time | Memory | Grader output | 
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