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 ) )

mp = dict()
_ = 0
for key in bag:
  mp[ key ] = _
  _ += 1
G = [ [] for i in range( N ) ]
for i in range( N ):
  G[ i ].append( mp[ ( R0[ i ], C0[ i ] ) ] )
  G[ i ].append( mp[ ( R1[ i ], C1[ i ] ) ] )

def dfs( u, bf, vis = None ):
  if vis == None:
    vis = [ False for i in range( len( mp ) ) ]
  for i in range( len( G[ u ] ) ):
    if vis[ G[ u ][ i ] ]: continue
    vis[ G[ u ][ i ] ] = True
    if bf[ G[ u ][ i ] ] == -1 or dfs( bf[ G[ u ][ i ] ], bf, vis ):
      bf[ G[ u ][ i ] ] = u
      return True
  return False

bf = [ -1 for i in range( len( mp ) ) ]
for i in range( N ):
  if not dfs( i, bf ):
    exit( print( "NO" ) )
print( "YES" )