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

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

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