import sys, time, random, heapq, math, itertools
from collections import deque, Counter, defaultdict
#from sortedcontainers import SortedSet, SortedList
from bisect import bisect, bisect_left, bisect_right
import heapq as hq
from functools import cache, cmp_to_key
def debug(*x):print('debug:',*x, file=sys.stderr)
sys.setrecursionlimit(300000)
input = lambda: sys.stdin.readline().rstrip()
ii = lambda: int(input())
mi = lambda: map(int, input().split())
li = lambda: list(mi())
inf = 2 ** 61 - 1
mod = 998244353

N = ii()
AB = set()
for i in range(N):
    a,b = map(int,input().split())
    if (a,b) in AB:
        print("Yes")
        exit()
    else:
        AB.add((a,b))
print("No")