list_points = []
for _ in xrange(input()):
    x, y = raw_input().split(' ')
    list_points.append((x, y))

x1 = list_points[0][0]
y1 = list_points[0][1]
flagx = 1
flagy = 1
for i in list_points:
    if i[0] != x1:
        flagx = 0
        break
for i in list_points:
    if i[1] != y1:
        flagy = 0
        break
if flagx == 1 or flagy == 1:
    print 'YES'
else:
    print 'NO'