#include <bits/stdc++.h>
using namespace std;

#define NDEBUG
#include <cassert>

typedef long long ll;
typedef long double Double;
typedef unsigned long long ull;
typedef pair<int,int> ii;
typedef pair<ll,ll> llll;
typedef pair<double,double> dd;

typedef vector<int> vi;
typedef vector<vector<int>> vvi;
typedef vector<ii> vii;
typedef vector<vector<ii>> vvii;
typedef vector<ll> vll;
typedef vector<string> vs;
typedef vector<double> vd;
typedef vector<long double> vD;

#define sz(a)  int((a).size())
#define pb  push_back
#define FOR(var,from,to) for(int var=(from);var<=(to);++var)
#define rep(var,n)  for(int var=0;var<(n);++var)
#define rep1(var,n)  for(int var=1;var<=(n);++var)
#define repC2(vari,varj,n)  for(int vari=0;vari<(n)-1;++vari)for(int varj=vari+1;varj<(n);++varj)
#define ALL(c)  (c).begin(),(c).end()
#define RALL(c)  (c).rbegin(),(c).rend()
#define tr(i,c)  for(auto i=(c).begin(); i!=(c).end(); ++i)
#define found(s,e)  ((s).find(e)!=(s).end())
#define mset(arr,val)  memset(arr,val,sizeof(arr))
#define mid(x,y) ((x)+((y)-(x))/2)
#define IN(x,a,b) ((a)<=(x)&&(x)<=(b))
#define cons make_pair


ll gcd(ll a, ll b) { while(a) swap(a, b%=a); return b; }

const ll MOD=1000000007LL;

ll ADD(ll x, ll y) { return (x+y) % MOD; }
ll SUB(ll x, ll y) { return (x-y+MOD) % MOD; }
ll MUL(ll x, ll y) { return x*y % MOD; }
ll POW(ll x, ll e) { ll v=1; for(; e; x=MUL(x,x), e>>=1) if (e&1) v = MUL(v,x); return v; }
ll DIV(ll x, ll y) { /*assert(y%MOD!=0);*/ return MUL(x, POW(y, MOD-2)); }

#define INTSPACE 12
char _buf[INTSPACE*1000000 + 3];

int loadint() {
    if (fgets(_buf, INTSPACE+3, stdin)==NULL) return 0;
    return atoi(_buf);
}

int loadvec(vector<int>& v, int N=-1) {
    if (N == 0) {
        v.clear();
        return 0;
    }
    if (N == -1) {
        N = loadint();
        if (N==0) return 0;
    }
    int bufsize = INTSPACE*N + 3;
    if (fgets(_buf, bufsize, stdin)==NULL) return 0;
    v.resize(N);

    int i=0;
    bool last = false;
    for (char *p=&_buf[0]; ;) {
        char *q = p;
        while (*q > ' ') ++q;
        if (*q == 0x0D || *q == 0x0A) last = true;
        *q = 0;
        v[i++] = atoi(p);
        if (last || i == N) break;
        p = q+1;
    }
    return i;
}
void read_cr() {
    fgets(_buf, 256, stdin);
}

bool solve(int N, vi& A, vi& _a, vi& _b) {
    if (N == 2) {
        return (A[0] == A[1]);
    }
    vvi ne(N);
    rep(i,N-1) {
        int ai = _a[i]-1, bi = _b[i]-1;
        assert(IN(ai, 0, N-1));
        assert(IN(bi, 0, N-1));
        assert(ai != bi);
        ne[ai].pb(bi);
        ne[bi].pb(ai);
    }
    vi ne_c(N);
    rep(i,N) ne_c[i] = ne[i].size();

    int max_at = (int)(max_element(ALL(ne_c)) - ne_c.begin());
    int root = max_at;

    queue<int> q;
    vi visited(N, false);
    vi order; order.reserve(N);
    vi parent(N, -1);
    q.push(root);
    while (!q.empty()){
        int u = q.front(); q.pop();
        visited[u] = true;
        order.pb(u);
        for (int v: ne[u]){
            if(visited[v]) continue;
            q.push(v);
            parent[v] = u;
        }
    }
    reverse(ALL(order));
    vvi gathered(N, vi());
    for (int u: order) {
        ll upwards = 0;
        if (gathered[u].empty()) {
            upwards = A[u];
        } else {
            sort(ALL(gathered[u]));
            ll a_b = A[u];
            ll a_2b = accumulate(ALL(gathered[u]), 0LL);
            ll b = a_2b - a_b, a = a_b - b;
            if (a < 0 || b < 0) return false;
            ll largest = gathered[u].back();
            if (a_2b - largest + a < largest) return false;
            upwards = a;
        }
        int p = parent[u];
        if (p == -1) {
            return (upwards == 0);
        }
        gathered[p].pb(upwards);
    }

    return false;
}

int main() {
    vi A;
    int N = loadvec(A);
    vi a(N-1), b(N-1);
    rep(i,N-1) scanf("%d %d", &a[i], &b[i]);
    cout << (solve(N,A,a,b) ? "YES":"NO") << endl;
    return 0;
}


Measured memory_bytes: 14848