class Rectangle():
    def __init__(self,w,h):
        self.width = w
        self.height = h

    def fitsInside(self,other):
        if self.width <= other.width and self.height <= other.height:
            return True
        elif self.width <= other.height and self.height <= other.width:
            return True
        else:
            return False

with open("rectangles.txt") as f:
    N = int(f.readline())

    txt = f.readline().split()
    prev = Rectangle(int(txt[0]),int(txt[1]))
    nests = True
    N -= 1
    while N > 0 and nests:
        txt = f.readline().split()
        next = Rectangle(int(txt[0]),int(txt[1]))
        nests = prev.fitsInside(next)
        prev = next
        N -= 1

if nests:
    print("The file contains a nesting sequence.")
else:
    print("The file does not contain a nesting sequence.")