// yukicoder: No.274 The Wall
// 2019.7.28 bal4u

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#if 1
#define gc() getchar_unlocked()
#else
#define gc() getchar()
#endif

int in() {   // 非負整数の入力
	int n = 0, c = gc();
	do n = 10 * n + (c & 0xf); while ((c = gc()) >= '0');
	return n;
}

typedef struct { int l, r; } T;
T tbl[2002]; int N, M;
char f[4002];

int cmp(const void *a, const void *b) {
	int t = ((T *)a)->l - ((T *)b)->l;
	if (t) return t;
	return ((T *)a)->r - ((T *)b)->r;
}

int check(int l, int r) {
	while (l <= r) if (f[l++]) return 0;
	return 1;
}

int main()
{
	int i, M;

	N = in(), M = in();
	if (N >= M) { puts("NO"); return 0; }
	for (i = 0; i < N; i++) {
		int l = in(), r = in();
		if (l <= M-1-r) tbl[i].l = l, tbl[i].r = r;
		else tbl[i].l = M-1-r, tbl[i].r = M-1-l;
	}
	qsort(tbl, N, sizeof(T), cmp);
	for (i = 0; i < N; i++) {
		if (check(tbl[i].l, tbl[i].r)) memset(f+tbl[i].l, 1, tbl[i].r-tbl[i].l+1);
		else if (check(M-1-tbl[i].r, M-1-tbl[i].l))
			memset(f+M-1-tbl[i].r, 1, tbl[i].r-tbl[i].l+1);
		else break;
	}
	puts(i < N? "NO": "YES");
	return 0;
}