n = int(input())

a = [0 for i in range(n)]
b = [0 for i in range(n)]

for i in range(n):
    temp = [int(j) for j in input().split()]
    a[i] = temp[0]
    b[i] = temp[1]
    
a = set(a)
b = set(b)

if(len(a) == 1 and len(b) == 1):
    print("NO")
elif(len(a) == 1 or len(b) == 1):
    print("YES")
else:
    print("NO")