# include <bits/stdc++.h>

using namespace std;
const int N=1e6+5;
int a[N],dp[N],n,len;
int main(){
	cin>>n;
	for(int i = 1;i<=n;i++)
		cin>>a[i];
	dp[++len]=a[1];
	for(int i = 2;i<=n;i++){
		if(a[i]>=dp[len]){
			dp[++len]=a[i];
		}else{
			int pos=lower_bound(dp+1,dp+len+1,a[i])-dp;
			dp[pos]=a[i];
		}
	}
	if(len>=n-1)cout<<"YES";
	else cout<<"NO";
	return 0;
}