def e(a,b,c):return(b[0]-a[0])*(c[1]-a[1])-(b[1]-a[1])*(c[0]-a[0])
def c(a):
    b=[]
    for p in a:
        while len(b)>1 and e(b[-1],b[-2],p)>=0:b.pop()
        b.append(p)
    t=len(b)
    for i in range(len(a)-2,-1,-1):
        while len(b)>t and e(b[-1],b[-2],a[i])>=0:b.pop()
        b.append(a[i])
    return b
n=int(input())
print("Yes"if len(c(sorted([list(map(int,input().split()))for _ in range(n)])))==n+1 else"No")