pat甲级1038

using namespace std;
const int maxn = 1e5+5;
const int INF = 0x3f3f3f3f;
const double eps = 1e-6;
typedef long long ll;
#define pb push_back

vector<string> v;
bool  (const string &a,const string &b) {
	int maxx = max(a.size(),b.size());
	int i = 0;
	while (i < maxx) {
		if (a[i%a.size()] < b[i%b.size()])
			return true;
		else if (a[i%a.size()] > b[i%b.size()])
			return false;
		i++;
	}
	return true;
}

看到大佬有简便的写法
bool cmp (const string &a,const string &b) {
	return a + b < b + a;
}
*/
int main() {
#ifdef ONLIGE_JUDGE
#else
    //freopen("H:\in.txt","r",stdin);
#endif // ONLIGE_JUDGE
	string s;
	int n; 
	cin >> n;
	for (int i = 0; i < n; ++i) {
		cin >> s;
		v.pb(s);
	}
	sort(v.begin(),v.end(),cmp);
	s = "";
	for (int i = 0; i < v.size(); ++i) {
		s += v[i];
	}
	while (s[0] == '0' && s.size() - 1 > 0) {
		s.erase(s.begin());
	} 
	cout << s << endl;
    return 0;
}