n = int(input())
l=[]
cx=0
cy=0
for i in range(n):
    x,y=input().split(' ')
    l.append([int(x),int(y)])
tx=l[0][0]
ty=l[0][1]
for i in range(n):
    if(tx!=l[i][0]):
        cx=1
for i in range(n):
    if(ty!=l[i][1]):
        cy=1
if(cx==1 and cy==1):
    print("NO")
else:
    print("YES")