29.2

#include <cstdio>
#include <string>
#include <vector>
#include <algorithm>

using namespace std;

const int MAX_LEN = (int)1e6 + 10;
const int M = 255;
const int N = M + M;

struct Edge {
    int to;
    string word;
    Edge(int to, const string &s)
        : to(to), word(s) {
    }
    Edge() {
    }
};

vector<Edge> g[N];
vector<string> result;
char buffer[MAX_LEN];
int degIn[N], degOut[N];
bool used[N];

void addEdge() {
    Edge e;
    e.word = buffer;
    e.to = e.word.back() + M;
    g[buffer[0] + M].push_back(e);
    ++degIn[e.to];
    ++degOut[buffer[0] + M];
}

void input() {
    int m;
    scanf("%d\n", &m);
    for (int i = 0; i < m; ++i) {
        gets(buffer);
        addEdge();
    }
}

void dfsCheck(int v) {
    used[v] = true;
    for (size_t i = 0; i < g[v].size(); ++i) {
        if (!used[g[v][i].to]) {
            dfsCheck(g[v][i].to);
        }
    }
}

bool checkConnectivity() {
    int c = 0;
    for (int i = 0; i < N; ++i) {
        if (degIn[i] + degOut[i] > 0 && !used[i]) {
            dfsCheck(i);
            ++c;
        }
    }
    return c < 2;
}

bool checkDegrees() {
    for (int i = 0; i < N; ++i) {
        if (degIn[i] != degOut[i]) {
            return false;
        }
    }
    return true;
}

void dfs(int v, const string &word) {
    while (g[v].size() > 0) {
        Edge e = g[v].back();
        g[v].pop_back();
        dfs(e.to, e.word);
    }
    result.push_back(word);
}

void getEulerCicle() {
    for (int i = 0; i < N; ++i) {
        if (degIn[i]) {
            dfs(i, "");
            break;
        }
    }
}

int main() {
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
    input();
    if (!checkConnectivity() || !checkDegrees()) {
        printf("No");
        return 0;
    }
    puts("Yes");
    getEulerCicle();
    reverse(result.begin(), result.end());
    for (size_t i = 1; i < result.size(); ++i) {
        puts(result[i].c_str());
    }
    return 0;
}