#include<iostream>
#include<vector>
#include<string>
#include<algorithm>	
#include<map>
#include<set>
#include<utility>
#include<cmath>
#include<cstring>
#include<queue>
#include<stack>
#include<cstdio>
#include<sstream>
#include<iomanip>
#include<assert.h>
#define loop(i,a,b) for(int i=a;i<b;i++) 
#define rep(i,a) loop(i,0,a)
#define pb push_back
#define mt make_tuple
#define all(in) in.begin(),in.end()
#define shosu(x) fixed<<setprecision(x)
using namespace std;
//kaewasuretyuui
typedef long long ll;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<pii> vp;
typedef vector<vp> vvp;
typedef vector<string> vs;
typedef vector<double> vd;
typedef tuple<int,int,int> tp;
typedef vector<tp> vt;
typedef vector<vd> vvd;
typedef pair<int,pii> pip;
typedef vector<pip>vip;
const double PI=acos(-1);
const double EPS=1e-7;
const int inf=1e9;
const ll INF=2e18;
int dx[]={0,1,0,-1};
int dy[]={1,0,-1,0};
int main(){
	int n,m;
	cin>>n>>m;
	assert(2<=n&&n<=1000&&0<=m&&m<=min(n*(n-1)/2,4000));
	vi in(n);
	rep(i,n)cin>>in[i];
	rep(i,n)assert(1<=in[i]&&in[i]<=1000000000);
	vvi fl(n,vi(2));
	bool h=false;
	map<pii,int>ma;
	rep(i,m){
		int a,b;
		cin>>a>>b;
		assert(1<=a&&a<b&&b<=n);
		assert(ma[pii(a,b)]==0);
		ma[pii(a,b)]=1;
		a--;b--;
		if(in[a]==in[b])continue;
		int t=in[a]>in[b]?0:1;
		if(fl[a][t  ]&&fl[a][t  ]!=in[b])h=true;
		if(fl[b][t^1]&&fl[b][t^1]!=in[a])h=true;
		fl[a][t  ]=in[b];
		fl[b][t^1]=in[a];
	}
	if(h)cout<<"YES"<<endl;
	else cout<<"NO"<<endl;
}