/* -*- 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], cnts[MAX_D + 1];

/* subroutines */

/* main */

int main() {
  int mind = MAX_D + 1, maxd = 0;
  
  for (int i = 0; i < N; i++) {
    cin >> ds[i];
    if (mind > ds[i]) mind = ds[i];
    if (maxd < ds[i]) maxd = ds[i];
    cnts[ds[i]]++;
  }

  bool ok = true;

  if (cnts[mind] > 1 || cnts[maxd] > 1) ok = false;
  else
    for (int d = mind + 1; ok && d < maxd; d++)
      if (cnts[d] > 2) ok = false;

  cout << (ok ? "YES" : "NO") << endl;
  return 0;
}