#include <iostream>
#include <algorithm>
using namespace std;

typedef pair<int,int> P;

int det(P a, P b) {
    return a.first * b.second - a.second * b.first;
}

P operator-(P a, P b) {
    return make_pair(a.first-b.first,a.second-b.second);
}

bool cmp(P a, P b) {
    if (a.first == b.first)
        return a.second > b.second;
    else
        return a.first < b.first;
}

int main() {
    int i, k, t;
    P p[5], out[5];
    for (i = 0; i < 5; i++) {
        int x, y;
        cin >> x >> y;
        p[i] = make_pair(x,y);
    }
    sort(p,p+5,cmp);
    k = 0;
    for (i = 0; i < 5; i++) {
        while (k > 1 && det(out[k-1]-out[k-2],p[i]-out[k-1]) <= 0) k--;
        out[k++] = p[i];
    }
    for (i = 4, t = k; i >= 0; i--) {
        while (k > t && det(out[k-1]-out[k-2],p[i]-out[k-1]) <= 0) k--;
        out[k++] = p[i];
    }
    k--;
    if (k == 5)
        cout << "YES" << endl;
    else
        cout << "NO" << endl;
    return 0;
}