n = int(input())
xp = []
yp = []
for i in range(n):
    s = [int(x) for x in input().split()]
    xp.append(s[0])
    yp.append(s[1])
x, y =[float(s) for s in input().split()]
def inPolygon(x, y, xp, yp):
    c = 0
    for i in range(n):
        if (((yp[i] <= y and y < yp[i - 1]) or (yp[i - 1] <= y and y < yp[i])) and (x > (xp[i - 1] - xp[i]) * (y - yp[i]) / (yp[i - 1] - yp[i]) + xp[i])):
            c = 1 - c
    return c
a =inPolygon(x,y,xp,yp)
if a == 1:
    print('YES')
else:
    print('NO')