#include<iostream>
#include<vector>
#include<algorithm>

int main() {
	int block_num, block_length;

	std::cin >> block_num >> block_length;
	
	std::vector<std::pair<int, int> > blocks;
	for (int i = 0; i < block_num; i++) {
		int left, right;
		std::cin >> left >> right;
		blocks.push_back(std::make_pair(left, right));
	}

	std::vector<int> wall(block_length, 0);
	int max = 0;
	int max_index = 0;
	while(blocks.size() != 0) {
		for (int i = 0; i < blocks.size(); i++) {
			if (max < blocks[i].second - blocks[i].first + 1) {
				max = blocks[i].second - blocks[i].first + 1;
				max_index = i;
			}
		}
		for (int i = blocks[max_index].first; i <= blocks[max_index].second; i++) {
			if(wall[i] == 0){
				wall[i] = 1;
			} else{
				for (int i = block_length - blocks[max_index].first - 1; i >= block_length - blocks[max_index].second - 1; i--){
					if(wall[i] == 0){
						wall[i] = 1;
					}else{
						std::cout << "NO" << std::endl;
						return 0;
					}
				}
			}
		}
		blocks.erase(blocks.begin() + max_index);
		max = 0;
	}
	std::cout << "YES" << std::endl;
	return 0;
}