# Enter your code here. Read input from STDIN. Print output to STDOUT
point_count = int(raw_input())

game = []

for p in xrange(point_count):
    game.append([int(x) for x in raw_input().strip().split()])

is_x = True
is_y = True

x_val = game[0][0]
y_val = game[0][1]
for p in xrange(1, point_count):
    this_point = game[p]
    
    if is_x and this_point[0] == x_val:
        is_x = True
    else:
        is_x = False
        
    if is_y and this_point[1] == y_val:
        is_y = True
    else:
        is_y = False
       
    
if is_x or is_y:
    print "YES"
else:
    print "NO"