#include <bits/stdc++.h>
using namespace std;
#define debug(x) cerr << #x << " == " << x << endl
#define el '\n'
typedef long long ll;
typedef double LD;
const int mod = 1000000007;
const int inf = 2147483647;
const int N = 200020;
const LD eps = 1e-12;
LD sqr(LD x) {
	return x * x;
}
struct point {
	LD x, y;
	point operator+(const point &a) const {
		return {x + a.x, y + a.y};
	}
	point operator-(const point &a) const {
		return {x - a.x, y - a.y};
	}
	point operator*(const LD a) const {
		return {a * x, a * y};
	}
	point operator/(const LD a) const {
		return {x / a, y / a};
	}
	//?????
	point rotate(LD t) const {
		return {x * cos(t) - y * sin(y), x * sin(t) - y * cos(t)};
	}
	//????90?
	point rotate_90() const {
		return {-y, x};
	}
	point unit() const {
		return *this / sqrt(sqr(x) + sqr(y));
	}
};
struct line {
	point s, t;
};
int sgn(LD x) {
	return x > eps ? 1 : (x < -eps ? -1 : 0);
}
//????????
LD dis(const point &a, const point &b) {
	return sqrt(sqr(a.x - b.x) + sqr(a.y - b.y));
}
//??
LD dot(const point &a, const point &b) {
	return a.x * b.x + a.y * b.y;
}
//??
LD det(const point &a, const point &b) {
	return a.x * b.y - a.y * b.x;
}
//?????
bool operator==(const point &a, const point &b) {
	return sgn(dot(a - b, a - b)) == 0;
}
//??????
bool same_dir(const line &a, const line &b) {
	return sgn(det(a.t - a.s, b.t - b.s)) == 0 &&
		   sgn(dot(a.t - a.s, b.t - b.s)) > 0;
}
//??????????????????
bool turn_left(const point &a, const point &b, const point &c) {
	return sgn(det(b - a, c - a)) > 0;
}
//??????????????????
bool turn_right(const point &a, const point &b, const point &c) {
	return sgn(det(b - a, c - a)) < 0;
}
//???????
bool point_on_line(const point &a, const line &l) {
	return sgn(det(l.s - a, a - l.t)) == 0;
}
//???????
bool point_on_segment(const point &a, const line &l) {
	return sgn(det(l.s - a, a - l.t)) == 0 &&
		   sgn(dot(l.s - a, a - l.t)) <= 0;
}
//???????????(????)
bool two_side(const point &a, const point &b, const line &c) {
	return sgn(det(a - c.s, c.t - c.s)) *
			   sgn(det(b - c.s, c.t - c.s)) ==
		   -1;
}
//??????
bool inter_judge(const line &a, const line &b) {
	if (point_on_segment(a.s, b) || point_on_segment(a.t, b) ||
		point_on_segment(b.s, a) || point_on_segment(b.t, a))
		return true;
	return two_side(a.s, a.t, b) && two_side(b.s, b.t, a);
}
//?????(????????)
point line_intersect(const line &a, const line &b) {
	LD u = det(a.t - a.s, b.s - a.s);
	LD v = det(a.t - a.s, b.t - a.s);
	return (b.s * v + b.t * u) / (u + v);
}
//???????
LD dist_point_to_line(const point &a, const line &b) {
	return fabs(det(b.t - b.s, a - b.s) / dis(b.s, b.t));
}
//???????
LD dist_point_to_segment(const point &a, const line &b) {
	if (sgn(dis(b.t, b.s)) == 0) {
		return dis(a, b.s);
	}
	if (sgn(dot(b.s - a, b.t - b.s)) * sgn(dot(b.t - a, b.t - b.s)) <=
		0) {
		return dist_point_to_line(a, b);
	}
	return min(dis(a, b.s), dis(a, b.t));
}
//??(?????????)
vector<point> convex_hull(vector<point> b) {
	sort(b.begin(), b.end(), [&](point x, point y) -> bool {
		if (sgn(x.x - y.x))
			return x.x < y.x;
		return x.y < y.y;
	});
	vector<point> a;
	a.push_back(b[0]);
	for (int i = 1; i < b.size(); i++) {
		if (b[i] != b[i - 1])
			a.push_back(b[i]);
	}
	if (a.size() <= 2)
		return a;
	vector<point> ret;
	for (int i = 0; i < (int)a.size(); i++) {
		while (ret.size() > 1 &&
			   turn_left(ret[ret.size() - 2], ret[ret.size() - 1],
						 a[i])) {
			ret.pop_back();
		}
		ret.push_back(a[i]);
	}
	int down_size = ret.size();
	for (int i = a.size() - 2; i >= 0; i--) {
		while (ret.size() > down_size &&
			   turn_left(ret[ret.size() - 2], ret[ret.size() - 1],
						 a[i])) {
			ret.pop_back();
		}
		ret.push_back(a[i]);
	}
	ret.pop_back();
	return ret;
}
void solve() {
	int n;
	LD ans = 0.00;
	cin >> n;
	vector<point> a, v;
	for (int i = 1; i <= n; i++) {
		point res;
		cin >> res.x >> res.y;
		a.push_back(res);
	}
	v = convex_hull(a);
	if(v.size()==n){
		cout<<"Yes"<<el;
	}else{
		cout<<"No"<<el;
	}
}
int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cout.tie(nullptr);
	int T= 1;
	// cin >> T;
	while (T--) {
		solve();
	}
	return 0;
}