#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
bool check(int a,int b,int c) { return a<c&&((b<a&&b<c)||(b>a&&b>c)); }
void solve() {
    int d[10],a[10];
    for(int i=1;i<=7;i++) cin>>d[i],a[i]=i;
    do {
        bool flag=true;
        for(int i=1;i<=5;i++) if(!check(d[a[i]],d[a[i+1]],d[a[i+2]])) { flag=false; break; }
        if(flag) return puts("YES"),void();
    }while(next_permutation(a+1,a+8));
    puts("NO");
}
int main() {
    //freopen("digit.in","r",stdin);
    //freopen("digit.out","w",stdout);
    ios::sync_with_stdio(false),cin.tie(nullptr);
    int t=1;
    while(t--) solve();
    return 0;
}