A11567 | Visiting a Friend

Pig is visiting a friend.

Pig's house is located at point $0$ , and his friend's house is located at point $m$ on an axis.

Pig can use teleports to move along the axis.

To use a teleport, Pig should come to a certain point (where the teleport is located) and choose where to move: for each teleport there is the rightmost point it can move Pig to, this point is known as the limit of the teleport.

Formally, a teleport located at point $x$ with limit $y$ can move Pig from point $x$ to any point within the segment $[x;y]$ , including the bounds.

Determine if Pig can visit the friend using teleports only, or he should use his car.

The first line contains two integers $n$ and $m$ ( $1<=n<=100,1<=m<=100$ ) — the number of teleports and the location of the friend's house.

The next $n$ lines contain information about teleports.

The $i$ -th of these lines contains two integers $a_{i}$ and $b_{i}$ ( $0<=a_{i}<=b_{i}<=m$ ), where $a_{i}$ is the location of the $i$ -th teleport, and $b_{i}$ is its limit.

It is guaranteed that $a_{i}>=a_{i-1}$ for every $i$ ( $2<=i<=n$ ).

Print "YES" if there is a path from Pig's house to his friend's house that uses only teleports, and "NO" otherwise.

You can print each letter in arbitrary case (upper or lower).