Package for this problem was not updated by the problem writer or Codeforces administration after we’ve upgraded the judging servers. To adjust the time limit constraint, solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then value 800 ms will be displayed and used to determine the verdict.

Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ACM-ICPC mode for virtual contests.
If you've seen these problems, a virtual contest is not for you - solve these problems in the archive.
If you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.
Never use someone else's code, read the tutorials or communicate with other person during a virtual contest.

No tag edit access

A. Spit Problem

time limit per test

2 secondsmemory limit per test

256 megabytesinput

standard inputoutput

standard outputIn a Berland's zoo there is an enclosure with camels. It is known that camels like to spit. Bob watched these interesting animals for the whole day and registered in his notepad where each animal spitted. Now he wants to know if in the zoo there are two camels, which spitted at each other. Help him to solve this task.

The trajectory of a camel's spit is an arc, i.e. if the camel in position *x* spits *d* meters right, he can hit only the camel in position *x* + *d*, if such a camel exists.

Input

The first line contains integer *n* (1 ≤ *n* ≤ 100) — the amount of camels in the zoo. Each of the following *n* lines contains two integers *x*_{i} and *d*_{i} ( - 10^{4} ≤ *x*_{i} ≤ 10^{4}, 1 ≤ |*d*_{i}| ≤ 2·10^{4}) — records in Bob's notepad. *x*_{i} is a position of the *i*-th camel, and *d*_{i} is a distance at which the *i*-th camel spitted. Positive values of *d*_{i} correspond to the spits right, negative values correspond to the spits left. No two camels may stand in the same position.

Output

If there are two camels, which spitted at each other, output YES. Otherwise, output NO.

Examples

Input

2

0 1

1 -1

Output

YES

Input

3

0 1

1 1

2 -2

Output

NO

Input

5

2 -10

3 10

0 5

5 -5

10 1

Output

YES

Codeforces (c) Copyright 2010-2017 Mike Mirzayanov

The only programming contests Web 2.0 platform

Server time: Jun/26/2017 23:55:21 (c3).

Desktop version, switch to mobile version.

User lists

Name |
---|