#include<bits/stdc++.h>
using namespace std;

struct Point {
    long double x,y;

    friend bool operator<(Point &a,Point &b) {
        if(a.x==b.x)return a.y<b.y;
        return a.x<b.x;
    }

    Point(long long x,long long y) {
        this->x=x;
        this->y=y;
    }
};

struct Line {
    long double A,B,C;

    Line(Point a,Point b) {
        this->A = b.y-a.y;
        this->B = a.x-b.x;
        this->C = a.y*b.x - a.x*b.y;
    }

    int contains(Point x) {
        if(A*x.x + B*x.y+C==0) return 1;
        return 0;
    }
};

struct Vector {
    long long x,y;

    Vector(Point a,Point b) {
        this->x=b.x-a.x;
        this->y=b.y-a.y;
    }
};

int n;
vector<Point> a;
void solve() {
    cin>>n;
    set<Point> st;
    for(int i=1;i<=n;i++) {
        long long x,y;
        cin>>x>>y;
        a.push_back(Point(x,y));
    }
    for(int i=0;i<n;i++) a.push_back(a[i]),st.insert(a[i]);
    if(st.size()!=n) return(void)(cout<<"No");

    int f=1;
    for(int i=1;i<=n;i++) {
        Vector x(a[i-1],a[i]),y(a[i],a[i+1]);
        if(x.x*y.y-x.y*y.x<=0) f=0;
    }

    if(f) return (void)(cout<<"Yes");

    f=1;
    for(int i=1;i<=n;i++) {
        Vector x(a[i-1],a[i]),y(a[i],a[i+1]);
        if(x.x*y.y-x.y*y.x>=0) f=0;
    }

    if(f) return (void)(cout<<"Yes");

    cout<<"No";

}

/*
(1,0)
(0,1)
a.x*b.y-a.y*b.x>0 a在b右侧
*/

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0),cout.tie(0);

    int t=1;
    // cin>>t;
    while(t--)
    solve();
}

/*

*/

In file included from /usr/include/c++/13/string:49,
                 from /usr/include/c++/13/bitset:52,
                 from /usr/include/x86_64-linux-gnu/c++/13/bits/stdc++.h:52,
                 from answer.code:1:
/usr/include/c++/13/bits/stl_function.h: In instantiation of ‘constexpr bool std::less<_Tp>::operator()(const _Tp&, const _Tp&) const [with _Tp = Point]’:
/usr/include/c++/13/bits/stl_tree.h:2118:35:   required from ‘std::pair<std::_Rb_tree_node_base*, std::_Rb_tree_node_base*> std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_M_get_insert_unique_pos(const key_type&) [with _Key = Point; _Val = Point; _KeyOfValue = std::_Identity<Point>; _Compare = std::less<Point>; _Alloc = std::allocator<Point>; key_type = Point]’
/usr/include/c++/13/bits/stl_tree.h:2171:4:   required from ‘std::pair<std::_Rb_tree_iterator<_Val>, bool> std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_M_insert_unique(_Arg&&) [with _Arg = const Point&; _Key = Point; _Val = Point; _KeyOfValue = std::_Identity<Point>; _Compare = std::less<Point>; _Alloc = std::allocator<Point>]’
/usr/include/c++/13/bits/stl_set.h:514:25:   required from ‘std::pair<typename std::_Rb_tree<_Key, _Key, std::_Identity<_Tp>, _Compare, typename __gnu_cxx::__alloc_traits<_Alloc>::rebind<_Key>::other>::const_iterator, bool> std::set<_Key, _Compare, _Alloc>::insert(const value_type&) [with _Key = Point; _Compare = std::less<Point>; _Alloc = std::allocator<Point>; typename std::_Rb_tree<_Key, _Key, std::_Identity<_Tp>, _Compare, typename __gnu_cxx::__alloc_traits<_Alloc>::rebind<_Key>::other>::const_iterator = std::_Rb_tree<Point, Point, std::_Identity<Point>, std::less<Point>, std::allocator<Point> >::const_iterator; typename __gnu_cxx::__alloc_traits<_Alloc>::rebind<_Key>::other = std::allocator<Point>; typename __gnu_cxx::__alloc_traits<_Alloc>::rebind<_Key> = __gnu_cxx::__alloc_traits<std::allocator<Point>, Point>::rebind<Point>; typename _Alloc::value_type = Point; value_type = Point]’
answer.code:52:53:   required from here
/usr/include/c++/13/bits/stl_function.h:408:20: error: no match for ‘operator<’ (operand types are ‘const Point’ and ‘const Point’)
  408 |       { return __x < __y; }
      |                ~~~~^~~~~
In file included from /usr/include/c++/13/bits/stl_algobase.h:67,
                 from /usr/include/c++/13/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/13/bits/stdc++.h:51:
/usr/include/c++/13/bits/stl_iterator.h:583:5: note: candidate: ‘template<class _IteratorL, class _IteratorR>  requires  three_way_comparable_with<_IteratorR, _IteratorL, std::partial_ordering> constexpr std::compare_three_way_result_t<_IteratorL, _IteratorR> std::operator<=>(const reverse_iterator<_IteratorL>&, const reverse_iterator<_IteratorR>&)’ (reversed)
  583 |     operator<=>(const reverse_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/13/bits/stl_iterator.h:583:5: note:   template argument deduction/substitution failed:
/usr/include/c++/13/bits/stl_function.h:408:20: note:   ‘const Point’ is not derived from ‘const std::reverse_iterator<_IteratorL>’
  408 |       { return __x < __y; }
      |                ~~~~^~~~~
/usr/include/c++/13/bits/stl_iterator.h:1690:5: note: candidate: ‘template<class _IteratorL, class _IteratorR>  requires  three_way_comparable_with<_IteratorR, _IteratorL, std::partial_ordering> constexpr std::compare_three_way_result_t<_IteratorL, _IteratorR> std::operator<=>(const move_iterator<_IteratorL>&, const move_iterator<_IteratorR>&)’ (reversed)
 1690 |     operator<=>(const move_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/13/bits/stl_iterator.h:1690:5: note:   template argument deduction/substitution failed:
/usr/include/c++/13/bits/stl_function.h:408:20: note:   ‘const Point’ is not derived from ‘const std::move_iterator<_IteratorL>’
  408 |       { return __x < __y; }
      |                ~~~~^~~~~
In file included from /usr/include/c++/13/bits/stl_algobase.h:64:
/usr/include/c++/13/bits/stl_pair.h:819:5: note: candidate: ‘template<class _T1, class _T2> constexpr std::common_comparison_category_t<decltype (std::__detail::__synth3way(declval<_T1&>(), declval<_T1&>())), decltype (std::__detail::__synth3way(declval<_T2&>(), declval<_T2&>()))> std::operator<=>(const pair<_T1, _T2>&, const pair<_T1, _T2>&)’ (rewritten)
  819 |     operator<=>(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
      |     ^~~~~~~~
/usr/include/c++/13/bits/stl_pair.h:819:5: note:   template argument deduction/substitution failed:
/usr/include/c++/13/bits/stl_function.h:408:20: note:   ‘const Point’ is not derived from ‘const std::pair<_T1, _T2>’
  408 |       { return __x < __y; }
      |                ~~~~^~~~~
/usr/include/c++/13/bits/stl_iterator.h:601:5: note: candidate: ‘template<class _Iterator>  requires  three_way_comparable<_Iterator, std::partial_ordering> constexpr std::compare_three_way_result_t<_Iterator, _Iterator> std::operator<=>(const reverse_iter...