#include<iostream>

using namespace std;

int main() {

	int n,x;
	cin >> n >> x;
	int j;
	int a = 0;
	int b = n-1;
	int * mas = new int[n];
	for (int i = 0; i < n;++i)
		mas[i] = i + 1;

	for (int i = 0; i < 200;++i) {
		j = (int)((b - a) / 2);
		if (mas[j] < x)
			a = j;
		else if (mas[j] > x)
			b = j;
		else {
			cout << "yes";
			break;
		}
	}
return 0;
}