def cross3(a,b,c):return(b[0]-a[0])*(c[1]-a[1])-(b[1]-a[1])*(c[0]-a[0])
def convex_hull(ps):
    qs=[]
    L=len(ps)
    for p in ps:
        while len(qs)>1 and cross3(qs[-1],qs[-2],p)>=0:qs.pop()
        qs.append(p)
    t=len(qs)
    for i in range(L-2,-1,-1):
        p=ps[i]
        while len(qs) > t and cross3(qs[-1], qs[-2], p) >= 0:qs.pop()
        qs.append(p)
    return qs
N=int(input())
print("Yes"if len(convex_hull(sorted([list(map(int,input().split()))for _ in range(N)])))==N+1 else"No")