#include тут iostream
using namespace std;
int main()
{
int number1, number2, a1, a2, a3, a4;
cin >> number1;
cin >> number2;
a1 = number1 / 10;
a2 = number1 % 10;
a3 = number2 / 10;
a4 = number2 % 10;
if (a1 == a3 && a2 == a4)
{
cout << "YES";
}
else
{
cout << "NO";
}
return 0;
}