def f(ll):
 res=[]
 for x in ll:
  if x not in res:
   res.append(x)
 return res
 
n=int(input())
l=[]
for i in range(n):
 a,b=map(int,input().split())
 l.append([a,b])
if len(f(l))==n:
 print('No')
else:
 print('Yes')