#define _CRT_SECURE_NO_WARNINGS
#pragma comment(linker, "/STACK:16777216")

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <vector>
#include <string>
#include <unordered_map>
#include <queue>

using namespace std;

const int p = 239, m = 1e9 + 7;
vector < int > pw, hs;

struct st
{
    int len, d, cn;
    int hs;
    st() {}
    st(int len, int d, int hs, int cn) : len(len), d(d), hs(hs), cn(cn) {}
};

st up(st a, int l, int nw) {
    if (a.d > 0) {
        if (l == a.d) {
            return st(a.len + a.d, 0, 0ll, a.cn + 1);
        }
        if (l < a.d) {
            return st(a.len + l, a.d - l, a.hs - nw * pw[a.d - l], a.cn + 1);
        }
        if (l > a.d) {
            return st(a.len + a.d, a.d - l, nw - a.hs * pw[l - a.d], a.cn + 1);
        }
    }
    else {
        a.d = -a.d;
        auto ans = up(a, l, nw);
        ans.d = -ans.d;
        return ans;
    }
}

unordered_map < int, vector < pair < int, int > > > q;
unordered_map < int, pair < st, int > > pr;
unordered_map < int, bool > us;
vector < vector < int > > hsh;
st ans(-1, 0, 0ll, 0);

int hh(st a) {
    return a.hs * p * p + a.len * p + a.d;
}

bool bfs(st cur) {
    queue < st > w;
    w.push(cur);
    us[hh(cur)] = 1;
    while (!w.empty()) {
        auto now = w.front();
        w.pop();
        int h = hh(now);
        if (now.len > 20000)
            continue;
        if (!now.d && now.len && now.cn > 2) {
            ans = now;
            return 1;
        }
        for (auto i : q[now.hs]) {
            auto nx = up(now, i.second, hs[i.first]);
            int n = hh(nx);
            if (!us[n]) {
                pr[n] = { now, i.first };
                w.push(nx);
                us[n] = 1;
            }
        }
    }
    return 0;
}

int main() {
    iostream::sync_with_stdio(0);
    int n;
    cin >> n;
    pw.resize(101, 1);
    for (int i = 1; i < 101; i++)
        pw[i] = pw[i - 1] * p;
    hs.resize(n);
    vector < string > a(n);
    hsh.resize(n);
    for (int i = 0; i < n; i++) {
        cin >> a[i];
        hsh[i].resize(a[i].length() + 1, 0);
        for (int j = 1; j <= a[i].length(); j++)
            hsh[i][j] = hsh[i][j - 1] * p + a[i][j - 1];
        hs[i] = hsh[i][a[i].length()];
    }
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            if (i == j)
                continue;
            for (int len = 1; len <= a[i].length(); len++) {
                int now = min(len, (int)a[j].length());
                int h = hsh[i][a[i].length()] - hsh[i][a[i].length() - len] * pw[len];
                int h1 = hsh[i][a[i].length() - (len - now)] - hsh[i][a[i].length() - len] * pw[now];
                int h2 = hsh[j][now];
                if (h1 == h2) {
                    q[h].push_back({ j, a[j].length() });
                }
            }
        }
    }
    for (int i = 0; i < n; i++) {
        int h = hh(st(0, a[i].length(), hsh[i][a[i].length()], 1));
        pr[h] = { st(0, 0, 0, 0), i };
        if (bfs(st(0, a[i].length(), hsh[i][a[i].length()], 1)))
            break;
    }
    if (ans.len == -1) {
        cout << "NO\n";
        return 0;
    }
    cout << "YES\n";
    st start = st(0, 0, 0, 0);
    vector < string > ans1, ans2;
    while ((start.d != ans.d) || (start.len != ans.len) || (start.hs != ans.hs) || (start.cn != ans.cn)) {
        int h = hh(ans);
        auto p = pr[h].first;
        if (ans.d > p.d) {
            ans1.push_back(a[pr[h].second]);
        }
        else {
            ans2.push_back(a[pr[h].second]);
        }
        ans = pr[h].first;
    }
    reverse(ans1.begin(), ans1.end());
    for (string s : ans1)
        cout << s;
    return 0;
}