n = int(input())
xc = []
yc = []

for _ in range(n):
    x, y = map(int, input().split())
    
    xc.append(x)
    yc.append(y)

same_line = False

for i in range(1, n):
    if(xc[i-1] != xc[i]):
        break
else:
    same_line = True

for i in range(1, n):
    if(yc[i-1] != yc[i]):
        break
else:
    same_line = True

print("YES" if same_line else "NO")