#include<bits/stdc++.h>
using namespace std;
int main(){
int n,k;
cin>>k>>n;
int t;
int arr;
set<int>c;
for(int i=0;i<k;i++){
cin>>t;
arr= arr+t;
}
for(int...
#include<cstdio>
using namespace std;
int n,i,la,nw,fl,tp;
int main(){
for(scanf("%d%d",&n,&la);++i<n;la=nw,fl=tp)
if(scanf("%d",&nw),fl>(tp=(nw>la?0:(nw<la?2:1))))return puts("NO");
return puts("YES");
}
#include<set>
#include<map>
#include<cmath>
#include<queue>
#include<cctype>
#include<vector>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;
#define fi first
#define se second
#define mp make_pair
#define...
#include<iostream>
#include<vector>
#include<algorithm>
#include<cstring>
#include<cstdio>
#include<cmath>
#include<cstdlib>
#include<ctime>
#include<queue>
#include<set>
using namespace std;
typedef long long LL;
const int N=4e5;
int gi()...