#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
//#include<cctype>
#include<climits>
#include<iostream>
#include<string>
#include<vector>
#include<map>
//#include<list>
#include<queue>
#include<deque>
#include<algorithm>
//#include<numeric>
#include<utility>
#include<complex>
//#include<memory>
#include<functional>
#include<cassert>
#include<set>
#include<stack>
#include<random>

const int dx[] = {1, 0, -1, 0};
const int dy[] = {0, 1, 0, -1};
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef pair<int, int> pii;

bool isKadomatsu(const vector<int>& A) {
    if (A[0] == A[1] || A[0] == A[2] || A[1] == A[2]) return false;
    if (A[0] > A[1] && A[1] < A[2]) return true;
    if (A[0] < A[1] && A[1] > A[2]) return true;
    return false;
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    vector<int> D(7);
    for (int i = 0; i < 7; i++) cin >> D[i];
    do {
        bool ok = true;
        for (int i = 0; i+3 <= 7; i++) {
            vector<int> A(3);
            for (int j = 0; j < 3; j++) A[j] = D[i+j];
            ok &= isKadomatsu(A);
        }
        for (int i = 0; i+2 < 7; i++) ok &= D[i]<D[i+2];
        if (ok) {
            cout << "YES" << endl;
            return 0;
        }
    } while (next_permutation(D.begin(), D.end()));
    cout << "NO" << endl;
    return 0;
}