n = int(raw_input().strip())
coords = []
for a0 in xrange(n):
    x,y = raw_input().strip().split(' ')
    x,y = [int(x),int(y)]
    coords.append([x, y])
    
if coords[0][0] == coords[1][0]:
    horizontal_value = coords[0][0]
    for coord in coords[2:]:
        if coord[0] != horizontal_value:
            print "NO"
            exit(0)
    print "YES"
elif coords[0][1] == coords[1][1]:
    vertical_value = coords[0][1]
    for coord in coords[2:]:
        if coord[1] != vertical_value:
            print "NO"
            exit(0)
    print "YES"
else:
    print "NO"