Problem Statement

There are N people. The family name and given name of the $i-th person (1 \leq i \leq N)$ are S_i and T_i, respectively.
Determine whether there is a pair of people with the same family and given names. In other words, determine whether there is a pair of integers (i,j) such that $1 \leq i \lt j \leq N, S_i=S_j$, and T_i=T_j.

Input

Input is given from Standard Input in the following format:
N
S_1 T_1
S_2 T_2
$\hspace{0.6cm}\vdots$
S_N T_N

Output

If there is a pair of people with the same family and given names, print Yes; otherwise, print No.

Constraints

• $2 \leq N \leq 1000$
• N is an integer.
• Each of S_i and T_i is a string of length between 1 and 10 (inclusive) consisting of English lowercase letters.

Sample Input 1

3
tanaka taro
sato hanako
tanaka taro

Sample Output 1

Yes

The first and third persons have the same family and given names.

Sample Input 2

3
saito ichiro
saito jiro
saito saburo

Sample Output 2

No

No two persons have the same family and given names.

Sample Input 3

4
sypdgidop bkseq
bajsqz hh
ozjekw mcybmtt
qfeysvw dbo

Sample Output 3

No

见题面 Input 部分

见题面 Output 部分