#include<iostream>
#include<string>
#include<fstream>
#include<iomanip>
#include<vector>
#include<cctype>
#include<algorithm>
using namespace std;

int main()
{
	string s, t, ss, tt;
	cin >> s;
	cin >> t;
	for (int i = 0; i < 5;i++)
	{
		if (i % 2 == 0)
		{
			ss += s[i];
			tt += t[i];
		}
	}
	if (ss >= tt)cout << "YES" << endl;
	else cout << "NO" << endl;
	return 0;
}