#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
typedef pair<ll, ll> p_ll;

template<class T>
void debug(T itr1, T itr2) { auto now = itr1; while(now<itr2) { cout << *now << " "; now++; } cout << endl; }
#define repr(i,from,to) for (ll i=(ll)from; i<(ll)to; i++)
#define all(vec) vec.begin(), vec.end()
#define rep(i,N) repr(i,0,N)
#define per(i,N) for (int i=(int)N-1; i>=0; i--)

const ll MOD = pow(10,9)+7;
const ll LLINF = pow(2,61)-1;
const int INF = pow(2,30)-1;

vector<ll> fac;
void c_fac(int x=pow(10,6)+10) { fac.resize(x,true); rep(i,x) fac[i] = i ? (fac[i-1]*i)%MOD : 1; }
ll modpow(ll x, ll p) { ll result = 1, now = 1, pm = x; while (now<=p) { if (p&now) { result = result * pm % MOD; } now*=2; pm = pm*pm % MOD; } return result; }
ll inv(ll a, ll m=MOD) { ll b = m, x = 1, y = 0; while (b!=0) { int d = a/b; a -= b*d; swap(a,b); x -= y*d; swap(x,y); } return (x+m)%m; }
ll nck(ll n, ll k) { return fac[n]*inv(fac[k]*fac[n-k]%MOD)%MOD; }
ll gcd(ll a, ll b) { if (a<b) swap(a,b); return b==0 ? a : gcd(b, a%b); }
ll lcm(ll a, ll b) { return a/gcd(a,b)*b; }

// ----------------------------------------------------------------------
// ----------------------------------------------------------------------

struct UnionFind {
  vector<ll> par, s; 
  UnionFind(ll N) : par(N), s(N) { rep(i,N) { par[i] = i; s[i] = 1; } }
  ll root(ll x) { return par[x]==x ? x : par[x] = root(par[x]); }
  ll size(ll x) { return par[x]==x ? s[x] : s[x] = size(root(x)); }
  void unite(ll x, ll y) { ll rx=root(x), ry=root(y); if (rx!=ry) { s[rx] += s[ry]; par[ry] = rx; } }
  bool same(ll x, ll y) {  ll rx=root(x), ry=root(y); return rx==ry; }
};

// ----------------------------------------------------------------------
// ----------------------------------------------------------------------

int main() {
  ll N, M; cin >> N >> M;
  ll B[N]; rep(i,N) cin >> B[i];
  ll l[M], r[M]; rep(i,M) { cin >> l[i] >> r[i]; l[i]--; }

  rep(i,N) if (i%2==1) B[i] *= -1;
  UnionFind uf(N+1);
  rep(i,N+1) {
    if (i==0) uf.s[i] = B[i];
    else if (i==N) uf.s[i] = -1*B[i-1];
    else uf.s[i] = B[i] - B[i-1];
  }
  // debug(diff,diff+(N+1));

  rep(i,M) uf.unite(l[i],r[i]);
  string result = "YES";
  rep(i,N+1) if (uf.root(i)==i&&uf.s[i]!=0) result = "NO";
  cout << result << endl;
  return 0;
}