#include <bits/stdc++.h>
  
using namespace std;
  
#define rep(i,n) REP(i,0,n)
#define REP(i,s,e) for(int i=(s); i<(int)(e); i++)
#define repr(i, n) REPR(i, n, 0)
#define REPR(i, s, e) for(int i=(int)(s-1); i>=(int)(e); i--)
#define pb push_back
#define all(r) r.begin(),r.end()
#define rall(r) r.rbegin(),r.rend()
#define fi first
#define se second
  
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
 
const int INF = 1e9;
const ll MOD = 1e9 + 7;
double EPS = 1e-8;

const int MAX_N = 1010;
vector<int> es[MAX_N];


int main(){
    int n, m;
    cin >> n >> m;
    vi v(n);
    rep(i, n) cin >> v[i];
    rep(i, m) {
        int a, b;
        cin >> a >> b;
        --a;--b;
        es[a].pb(b);
        es[b].pb(a);
    }
    string yes = "YES", no = "NO";
    rep(i, n) {
        set<int> st[2];
        for(auto& to: es[i]) {
            if(v[to] != v[i]) st[v[to] < v[i]].insert(v[to]);
        }
        if(st[0].size() >= 2 || st[1].size() >= 2) {
            cout << yes << endl;
            return 0;
        }
    }
    cout << no << endl;
    return 0;
}