While dad was at work, a little girl Tanya decided to play with dad's password to his secret database. Dad's password is a string consisting of n + 2 characters. She has written all the possible n three-letter continuous substrings of the password on pieces of paper, one for each piece of paper, and threw the password out. Each three-letter substring was written the number of times it occurred in the password. Thus, Tanya ended up with n pieces of paper.

Then Tanya realized that dad will be upset to learn about her game and decided to restore the password or at least any string corresponding to the final set of three-letter strings. You have to help her in this difficult task. We know that dad's password consisted of lowercase and uppercase letters of the Latin alphabet and digits. Uppercase and lowercase letters of the Latin alphabet are considered distinct.

Input

The first line contains integer n (1 ≤ n ≤ 2·105), the number of three-letter substrings Tanya got. 

Next n lines contain three letters each, forming the substring of dad's password. Each character in the input is a lowercase or uppercase Latin letter or a digit.

Output

If Tanya made a mistake somewhere during the game and the strings that correspond to the given set of substrings don't exist, print "NO". 

If it is possible to restore the string that corresponds to given set of substrings, print "YES", and then print any suitable password option.

Examples

Input

5
aca
aba
aba
cab
bac


Output

YES
abacaba


Input

4
abc
bCb
cb1
b13


Output

NO


Input

7
aaa
aaa
aaa
aaa
aaa
aaa
aaa


Output

YES
aaaaaaaaa
#include <bits/stdc++.h>
using namespace std;
template <class T>
inline T SQR(T x) {
  return x * x;
}
template <class T>
inline string TOSTR(const T &x) {
  stringstream ss;
  ss << x;
  return ss.str();
}
template <class T>
void UPDATE_MIN(T &x, T y) {
  if (y < x) {
    x = y;
  }
}
template <class T>
void UPDATE_MAX(T &x, T y) {
  if (x < y) {
    x = y;
  }
}
int gcd(int a, int b) { return a ? gcd(b % a, a) : b; }
long long gcd(long long a, long long b) { return a ? gcd(b % a, a) : b; }
long long powmod(long long a, long long p, long long m) {
  long long r = 1;
  while (p) {
    if (p & 1) r = r * a % m;
    p >>= 1;
    a = a * a % m;
  }
  return r;
}
const int MOD = 1000 * 1000 * 1000 + 7;
const double PI = 3.1415926535897932384626433832795l;
int N;
inline void copy(unsigned char *to, unsigned char *frm) {
  to[0] = frm[0];
  to[1] = frm[1];
  to[2] = frm[2];
}
unordered_set<int> nodes;
unordered_set<int> strings;
int indeg[(1 << 16)];
int outdeg[(1 << 16)];
vector<int> edges[(1 << 16)];
int indexes[(1 << 16)];
stack<int> result;
int start_node = 0;
void dfs(int v) {
  int sz = edges[v].size();
  while (indexes[v] < sz) {
    dfs(edges[v][indexes[v]++]);
  }
  result.push(v);
}
int main() {
  cin >> N;
  for (int(i) = 0; (i) < (int)(N); (i)++) {
    unsigned char s[10];
    scanf("%s", s);
    int str = (s[0] << 16) | (s[1] << 8) | s[2];
    strings.insert(str);
    unsigned short v1 = (s[0] << 8) | s[1];
    unsigned short v2 = (s[1] << 8) | s[2];
    edges[v1].push_back(v2);
    nodes.insert(v1);
    nodes.insert(v2);
    outdeg[v1]++;
    indeg[v2]++;
    start_node = v1;
  }
  int deg_sum = 0;
  for (auto v : nodes) {
    if (indeg[v] == outdeg[v] - 1) {
      start_node = v;
    }
    deg_sum += abs(indeg[v] - outdeg[v]);
  }
  dfs(start_node);
  for (auto v : nodes) {
    if (indexes[v] < edges[v].size()) {
      {
        printf("NO\n");
        exit(0);
      };
    }
  }
  string password;
  password += (char)((result.top()) >> 8);
  password += (char)((result.top()) & 0xff);
  int step = result.top();
  result.pop();
  while (!result.empty()) {
    password += (char)((result.top()) & 0xff);
    step = (step << 8) | (char)((result.top()) & 0xff);
    step &= 0xffffff;
    if (!strings.count(step)) {
      printf("NO\n");
      exit(0);
    };
    result.pop();
  }
  cout << "YES\n";
  cout << password;
  return 0;
}
