#include <iostream>
#include <algorithm>
#include <vector>
#include <string>
#include <iomanip>
#include <cmath>
#include <functional>
using namespace std;
#define diff(x,y) ((x > y) ? (x - y) : (y - x))
#define us(x) (x > 0) ? x : x * -1
#define lli long long int

int main() {
	int x1, x2, x3;
	int kaseki, now;
	char sute;
	cin >> x1 >> sute >> x2 >> sute >> x3;
	kaseki = x1 * 100 + x2 * 10 + x3;
	cin >> x1 >> sute >> x2 >> sute >> x3;
	now = x1 * 100 + x2 * 10 + x3;

	if (kaseki >= now)	cout << "YES" << endl;
	else				cout << "NO" << endl;

	return 0;
}