#yukicoder 3154 convex polygon judge

#Convex Hull: 凸包を求める  SortedP: (x, y)を辞書順昇順に並べた点群
def Convex_Hull(SortedP):
    outer_product = lambda x1, y1, x2, y2: x1 * y2 - x2 * y1
    stack = []
    for x, y in SortedP:  #上側凸包
        while len(stack) > 1:
            x1, y1 = stack[-2]
            x2, y2 = stack[-1]
            if outer_product(x2 - x1, y2 - y1, x - x2, y - y2) >= 0:
                stack.pop()  # > を >= にすると経路上の点を削除できる
            else: break
        stack.append((x, y))
    T = len(stack)
    for x, y in SortedP[-2::-1]:  #下側凸包
        while len(stack) > T:
            x1, y1 = stack[-2]
            x2, y2 = stack[-1]
            if outer_product(x2 - x1, y2 - y1, x - x2, y - y2) >= 0:
                stack.pop()
            else: break
        stack.append((x, y))
    return stack[:-1]



#テスト1: 凸包貼るだけ
N = int(input())
P = [tuple(map(int, input().split())) for _ in range(N)]
print('Yes' if len( Convex_Hull(sorted(P)) ) == N else 'No')