#include <iostream>#include <cstdlib>#include <cstring>#include <cstdio>#include <algorithm>using namespace std;#define maxn 1005#define maxl 100struct Word{ int id; int len;}word[maxn];int n, m;char st[maxn][maxl];bool vis[maxn];bool found;bool operator < (const Word &a, const Word &b){ return a.len < b.len;}void input(){ scanf("%d", &n); scanf("%s", st[n]); m = 0; int len1 = strlen(st[n]); found = false; for (int i = 0; i < n; i++) { scanf("%s", st[i]); if (strcmp(st[n], st[i]) == 0) found = true; word[m].id = i; word[m].len = strlen(st[i]); if (word[m].len > len1) m++; } if (!found) abort(); word[m].len = len1; word[m].id = n; m++;}bool match(char *st1, char *st2, int len){ int l = 0; while (l < len && st1[l] == st2[l]) l++; int r = len; while (r > 0 && st1[r - 1] == st2[r]) r--; return l >= r;}void work(){ memset(vis, 0, sizeof(vis)); vis[0] = true; for (int i = 0; i < m; i++) if (vis[i]) for (int j = i + 1; j < m && word[j].len <= word[i].len + 1; j++) if (!vis[j] && word[j].len == word[i].len + 1 && match(st[word[i].id], st[word[j].id], word[i].len)) vis[j] = true; int i = m - 1; while (!vis[i]) i--; printf("%sn", st[word[i].id]);}int main(){ input(); sort(word, word + m); work(); return 0;}
