/* -*- coding: utf-8 -*-
 *
 * 360.cc: No.360 増加門松列 - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int N = 7;
const int MAX_D = 100;

/* typedef */

/* global variables */

int ds[N], ps[N];

/* subroutines */

inline bool inc_kadomatsu(int a0, int a1, int a2) {
  return (a0 < a2 && (a1 > a2 || a1 < a0));
}

/* main */

int main() {
  for (int i = 0; i < N; i++) (cin >> ds[i]), ps[i] = i;

  bool ok = false;
  do {
    bool ng = false;
    for (int i = 0; i < N - 2; i++)
      if (! inc_kadomatsu(ds[ps[i]], ds[ps[i + 1]], ds[ps[i + 2]])) {
	ng = true;
	break;
      }
    if (! ng) {
      ok = true;
      break;
    }
  } while (next_permutation(ps, ps + N));
  
  cout << (ok ? "YES" : "NO") << endl;
  return 0;
}