N = int( input() )
R0 = []
C0 = []
R1 = []
C1 = []
bag = set()
for i in range( N ):
  r0, c0, r1, c1 = map( int, input().split() )
  R0.append( r0 )
  C0.append( c0 )
  bag.add( ( r0, c0 ) )
  R1.append( r1 )
  C1.append( c1 )
  bag.add( ( r1, c1 ) )

if len( bag ) + 1 <= N:
  print( "NO" )
else:
  print( "YES" )