n = input()
ans="YES"
x=[]
y=[]
x1,y1 = map(int,raw_input().split())
x.append(x1)
y.append(y1)
for i in range(n-1):
    x2,y2 = map(int,raw_input().split())
    x.append(x2)
    y.append(y2)
if x.count(x[0]) == len(x) or y.count(y[0]) == len(y):
    ans="YES"
else:
    ans="NO"
print ans