n=int(input())
s_sei=set()
t_mei=set()
st_total=set()
for i in range(n):
    s,t=map(str,input().split())
    s_sei.add(s)
    t_mei.add(t)
st_total=s_sei|t_mei
if len(s_sei)<n and len(t_mei)<n:
    print('No')
if len(s_sei)==n and len(t_mei)==n and len(st_total)<2*n:
    print('No')
else:
    print('Yes')