M

#define _CRT_SECURE_NO_DEPRECATE

#include <iostream>
#include <vector>
#include <string>
#include <map>
#include <set>
#include <algorithm>

#define li long long

using namespace std;

int main() {
	freopen("input.txt", "r", stdin);
	freopen("output.txt", "w", stdout);

	int n, x;
	cin >> n >> x;
	set<int> a;
	int r = -1;
	if (x % 2 == 0) {
		r = x / 2;
	}
	int k = 0;

	for (int i = 0; i < n; i++) {
		int c;
		cin >> c;
		a.insert(c);
		if (c == r) {
			k++;
		}
	}
	if (k > 1) {
		cout << "YES";
		return 0;
	}
	else {
		if (r != -1) {
			a.erase(r);
		}
	}
	for (auto i : a) {
		if (a.find(x - i) != a.end()) {
			cout << "YES";
			return 0;
		}
	}
	cout << "NO";
}