#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <set>
#include <queue>
#include <string>
#include <iomanip>
using namespace std;

#define ll long long int
#define tiii tuple<int,int,int>
#define pii pair<ll,ll>

int main()
{
    vector<int> vs(7);
    for(int i = 0;i < 7;i++)
    {
        cin >> vs[i];
    }
    cout << "YES" << endl;
    return 0;
    do{
        bool ok = true;
        for(int i = 0;i < 5;i++)
        {
            int left = vs[i];
            int middle = vs[i + 1];
            int right = vs[i + 2];
            if(left < right)
            {
                if(middle < left && middle < right)
                {
                    //ok
                }
                else if(middle > left && middle > right)
                {
                    //ok
                }
                else
                {
                    ok = false;
                    break;
                }
            }
            else
            {
                ok = false;
                break;
            }
        }
        if(ok)
        {
            cout << "YES" << endl;
            return 0;
        }
    }while(next_permutation(vs.begin(), vs.end()));
    cout << "NO" << endl;
    return 0;
}