N = int(input())
A = [list(map(int, input().split())) for i in range(N)]

a = 0
A.sort()
for i in range(N):
    if a == 1:
        break
    if A[i] == A[i + 1]:
        print("Yes")
        a = 1
        break

if a == 0:
  print("No")