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

typedef long long ll;
typedef vector< int > vi;
typedef vector< vi > vvi;
typedef vector< ll > vl;
typedef vector< vl > vvl;
typedef pair< int, int > pii;
typedef vector< pii > vp;
typedef vector< double > vd;
typedef vector< vd > vvd;
typedef vector< string > vs;

template< class T1, class T2 >
int upmin( T1 &x, T2 v ){
  if( x > v ){
    x = v;
    return 1;
  }
  return 0;
}

template< class T1, class T2 >
int upmax( T1 &x, T2 v ){
  if( x < v ){
    x = v;
    return 1;
  }
  return 0;
}

const int INF = 0x3f3f3f3f;
const string msg[] = { "NO", "YES" };

vp P;

void init(){
  P = vp( 5 );
  for( int i = 0; i < 5; ++i )
    cin >> P[ i ].first >> P[ i ].second;
}

vp convex_hull;

void preprocess(){
  sort( P.begin(), P.end() );
  for( int i = 0; i < P.size(); ++i ){
    while( convex_hull.size() >= 2 ){
      int sz = convex_hull.size();
      int dx1 = convex_hull[ sz - 1 ].first - convex_hull[ sz - 2 ].first;
      int dy1 = convex_hull[ sz - 1 ].second - convex_hull[ sz - 2 ].second;
      int dx2 = P[ i ].first - convex_hull[ sz - 2 ].first;
      int dy2 = P[ i ].second - convex_hull[ sz - 2 ].second;
      if( dx1 * dy2 - dx2 * dy1 <= 0 )
        convex_hull.pop_back();
      else
        break;
    }
    convex_hull.emplace_back( P[ i ] );
  }
  int k = convex_hull.size();
  for( int i = P.size() - 2; i >= 0; --i ){
    while( convex_hull.size() >= k + 1 ){
      int sz = convex_hull.size();
      int dx1 = convex_hull[ sz - 1 ].first - convex_hull[ sz - 2 ].first;
      int dy1 = convex_hull[ sz - 1 ].second - convex_hull[ sz - 2 ].second;
      int dx2 = P[ i ].first - convex_hull[ sz - 2 ].first;
      int dy2 = P[ i ].second - convex_hull[ sz - 2 ].second;
      if( dx1 * dy2 - dx2 * dy1 <= 0 )
        convex_hull.pop_back();
      else
        break;
    }
    convex_hull.emplace_back( P[ i ] );
  }
  if( convex_hull.size() > 1 )
    convex_hull.pop_back();      
}

void solve(){
  cout << msg[ convex_hull.size() == 5 ] << endl;
}

signed main(){
  ios::sync_with_stdio( 0 );
  init();
  preprocess();
  solve();
  return 0;
}