#include <cstdio>
#include <cstring>
#include <iostream>
#include <string>
#include <cmath>
#include <bitset>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <algorithm>
#include <complex>
#include <unordered_map>
#include <unordered_set>
#include <random>
#include <cassert>
#include <fstream>
#include <utility>
#include <functional>
#include <time.h>
#include <stack>
#include <array>
#define popcount __builtin_popcount
using namespace std;
using ll=long long;
typedef pair<int, int> P;

int main()
{
    int n, m; cin>>n>>m;
    ll b[100010];
    for(int i=0; i<n; i++){
        cin>>b[i];
        if(i&1) b[i]=-b[i];
    }
    ll d[100010];
    for(int i=1; i<n; i++){
        d[i]=b[i]-b[i-1];
    }
    d[0]=b[0], d[n]=-b[n-1];
    int l[100010], r[100010];
    vector<int> g[100010];
    for(int i=0; i<m; i++){
        cin>>l[i]>>r[i];
        l[i]--;
        g[l[i]].push_back(r[i]);
        g[r[i]].push_back(l[i]);
    }
    bool used[100010]={};
    auto dfs=[&](auto dfs, int x, ll &s)->void{
        s+=d[x];
        used[x]=1;
        for(auto y:g[x]){
            if(!used[y]){
                dfs(dfs, y, s);
            }
        }
    };
    for(int i=0; i<=n; i++){
        if(used[i]) continue;
        ll s=0;
        dfs(dfs, i, s);
        if(s!=0){
            cout<<"NO"<<endl;
            return 0;
        }
    }
    cout<<"YES"<<endl;
    return 0;
}