n = int(raw_input().strip())
points = []
for i in xrange(0,n):
    x,y = map(int,raw_input().strip().split(' '))
    points.append((x,y))
vert = True
horz = True
for j in xrange(0, len(points) - 1):
    if points[j][0] != points[j + 1][0]:
        vert = False
        break
for j in xrange(0, len(points) - 1):
    if points[j][1] != points[j + 1][1]:
        horz = False
        break
if vert or horz:
    print "YES"
else:
    print "NO"