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#include <bits/stdc++.h>

using namespace std;

#define cin_2d(vec, n, m) for(int i = 0; i < n; i++) for(int j = 0; j < m && cin >> vec[i][j]; j++);
#define cout_2d(vec, n, m) for(int i = 0; i < n; i++, cout << "\n") for(int j = 0; j < m && cout << vec[i][j] << " "; j++);
#define cout_map(mp) for(auto& [f, s] : mp) cout << f << "  " << s << "\n";
#define Time cerr << "Time Taken: " << (float)clock() / CLOCKS_PER_SEC << " Secs" << "\n";
#define fixed(n) fixed << setprecision(n)
#define ceil(n, m) (((n) / (m)) + ((n) % (m) ? 1 : 0))
#define fill(vec, value) memset(vec, value, sizeof(vec));
#define Num_of_Digits(n) ((int)log10(n) + 1)
#define mod_combine(a, b, m) (((a % m) * (b % m)) % m)
#define all(vec) vec.begin(), vec.end()
#define rall(vec) vec.rbegin(), vec.rend()
#define sz(x) int(x.size())
#define debug(x) cout << #x << ": " << (x) << "\n";
#define fi first
#define se second
#define ll long long
#define ull unsigned long long
#define Mod  1'000'000'007
#define OO 2'000'000'000
#define EPS 1e-9
#define PI acos(-1)
template < typename T = int > using Pair = pair < T, T >;

template < typename T = int > istream& operator >> (istream &in, vector < T > &v) {
    for (auto &x: v) in >> x;
    return in;
}

template < typename T = int > ostream& operator << (ostream &out, const vector < T > &v) {
    for (const T &x: v) out << x << ' ';
    return out;
}

void AhMeD_HoSSaM(){
    ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
    #ifndef ONLINE_JUDGE
        freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout);
    #endif
}

constexpr int N = 1e5, H = 128;
int n;
vector < vector < int > > adj;
vector < int > deg;
string res;

int Hash(char a, char b){
    return a * H + b;
}

void dfs(int u){
    int v;
    while(!adj[u].empty()){
        v = adj[u].back();
        adj[u].pop_back();
        dfs(v);
    }
    res += char(u % H);
}

void Solve(){
    cin >> n;
    adj = vector < vector < int > > (N);
    deg = vector < int > (N);
    vector < string > words(n - 2);
    set < int > keys;
    int Root = 0, Degrees = 0, Minus_Degrees = 0;
    for(auto& s : words){
        cin >> s;
        int u = Hash(s[0], s[1]), v = Hash(s[1], s[2]);
        adj[u].push_back(v), deg[v]--, deg[u]++;
        keys.insert(u), keys.insert(v), Root = u;
    }
    for(auto& k : keys){
        if(deg[k] > 0)
            Root = k, Degrees += deg[k];
        else if(deg[k] < 0)
            Minus_Degrees += deg[k];
    }
    dfs(Root);
    res += char(Root / H);
    reverse(all(res));
    if(sz(res) != n || Degrees > 1 || Minus_Degrees < -1)
        return cout << "NO\n", void();
    cout << "YES\n";
    cout << res << '\n';
}

int main(){
    AhMeD_HoSSaM();
    int t = 1;
    //cin >> t;
    while(t--)
        Solve();
    return 0;
}