#pragma GCC optimize ("O3")
#pragma GCC target ("sse4")

#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/rope>

using namespace std;
using namespace __gnu_pbds;
using namespace __gnu_cxx;
 
typedef long long ll;
typedef long double ld;
typedef complex<ld> cd;

typedef pair<int, int> pi;
typedef pair<ll,ll> pl;
typedef pair<ld,ld> pd;

typedef vector<int> vi;
typedef vector<ld> vd;
typedef vector<ll> vl;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
typedef vector<cd> vcd;

template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;

#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define F0R(i, a) for (int i = 0; i < (a); i++)
#define FORd(i, a, b) for (int i = (b) - 1; i >= (a); i--)
#define F0Rd(i, a) for (int i = (a) - 1; i >= 0; i--)
#define trav(a, x) for (auto& a : x)

#define mp make_pair
#define pb push_back
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound

#define sz(x) (int)x.size()
#define beg(x) x.begin()
#define en(x) x.end()
#define all(x) beg(x), en(x)
#define resz resize

const int MOD = 1e9 + 7;
const ll INF = 1e9;
const int MX = 1e5 + 5;
const ld PI = 4 * atan((ld)1);

template<class T> void ckmin(T &a, T b) { a = min(a, b); }
template<class T> void ckmax(T &a, T b) { a = max(a, b); }

namespace input {
    template<class T> void sc(complex<T>& x);
    template<class T1, class T2> void sc(pair<T1, T2>& p);
    template<class T> void sc(vector<T>& a);
    template<class T, size_t SZ> void sc(array<T, SZ>& a);

    template<class T> void sc(T& x) { cin >> x; }
    void sc(double& x) { string t; sc(t); x = stod(t); }
    void sc(ld& x) { string t; sc(t); x = stold(t); }
    template<class Arg, class... Args> void sc(Arg& first, Args&... rest) { sc(first); sc(rest...); }

    template<class T> void sc(complex<T>& x) { T a, b; sc(a, b); x = cd(a, b); }
    template<class T1, class T2> void sc(pair<T1, T2>& p) { sc(p.f, p.s); }
    template<class T> void sc(vector<T>& a) { F0R(i, sz(a)) sc(a[i]); }
    template<class T, size_t SZ> void sc(array<T, SZ>& a) { F0R(i,SZ) sc(a[i]); }
}

using namespace input;

namespace output {
    template<class T1, class T2> void pr(const pair<T1,T2>& x);
    template<class T, size_t SZ> void pr(const array<T,SZ>& x);
    template<class T> void pr(const vector<T>& x);
    template<class T> void pr(const set<T>& x);
    template<class T1, class T2> void pr(const map<T1,T2>& x);

    template<class T> void pr(const T& x) { cout << x; }
    template<class Arg, class... Args> void pr(const Arg& first, const Args&... rest) { pr(first); pr(rest...); }

    template<class T1, class T2> void pr(const pair<T1,T2>& x) { pr("{", x.f, ", ", x.s, "}"); }
    template<class T> void prContain(const T& x) { pr("{"); bool fst = 1; for (const auto& a: x) pr(!fst?", ":"", a), fst = 0; pr("}"); }
    template<class T, size_t SZ> void pr(const array<T,SZ>& x) { prContain(x); }
    template<class T> void pr(const vector<T>& x) { prContain(x); }
    template<class T> void pr(const set<T>& x) { prContain(x); }
    template<class T1, class T2> void pr(const map<T1,T2>& x) { prContain(x); }
    
    void ps() { pr("\n"); }
    template<class Arg> void ps(const Arg& first) { pr(first); ps(); }
    template<class Arg, class... Args> void ps(const Arg& first, const Args&... rest) { pr(first," "); ps(rest...); }
}

using namespace output;

namespace io {
    void setIn(string s) { freopen(s.c_str(), "r", stdin); }
    void setOut(string s) { freopen(s.c_str(), "w", stdout); }
    void setIO(string s = "") {
        ios_base::sync_with_stdio(0); cin.tie(0);
        if (sz(s)) { setIn(s + ".inp"), setOut(s + ".out"); }
    }
}

using namespace io;

template<class T> T invGeneral(T a, T b) {
    a %= b; if (a == 0) return b == 1 ? 0 : -1;
    T x = invGeneral(b, a); 
    return x == -1 ? -1 : ((1 - (ll)b * x) / a + b) % b;
}

template<class T> struct modular {
    T val; 
    explicit operator T() const { return val; }
    modular() { val = 0; }
    template<class U> modular(const U& v) {
        val = (-MOD <= v && v <= MOD) ? v : v % MOD;
        if (val < 0) val += MOD;
    }
    friend ostream& operator<<(ostream& os, const modular& a) { return os << a.val; }
    friend bool operator==(const modular& a, const modular& b) { return a.val == b.val; }
    friend bool operator!=(const modular& a, const modular& b) { return !(a == b); }

    modular operator-() const { return modular(-val); }
    modular& operator+=(const modular& m) { if ((val += m.val) >= MOD) val -= MOD; return *this; }
    modular& operator-=(const modular& m) { if ((val -= m.val) < 0) val += MOD; return *this; }
    modular& operator*=(const modular& m) { val = (ll)val * m.val % MOD; return *this; }
    friend modular exp(modular a, ll p) {
        modular ans = 1; for (; p; p /= 2, a *= a) if (p & 1) ans *= a;
        return ans;
    }
    friend modular inv(const modular& a) { return invGeneral(a.val, MOD); }
    modular& operator/=(const modular& m) { return (*this) *= inv(m); }
    
    friend modular operator+(modular a, const modular& b) { return a += b; }
    friend modular operator-(modular a, const modular& b) { return a -= b; }
    friend modular operator*(modular a, const modular& b) { return a *= b; }
    
    friend modular operator/(modular a, const modular& b) { return a /= b; }
};

typedef modular<int> mi;
typedef pair<mi,mi> pmi;
typedef vector<mi> vmi;
typedef vector<pmi> vpmi;

int n, root, tot;
int A[MX], deg[MX], now[MX];
int pre[MX * 2], child[MX * 2];

void add(int a, int b) {
    pre[++tot] = now[a];
    now[a] = tot;
    child[tot] = b;
}

ll dfs(int par, int u) {
    if (deg[u] == 1) {
        return A[u];
    }
    ll rm = A[u] * 2;
    for (int p = now[u], v = child[p]; p; p = pre[p], v = child[p]) {
        if (v != par) {
            ll tmp = dfs(u, v);
            if (tmp > A[u]) {
                ps("NO");
                exit(0);
            }
            rm -= tmp;
        }
    }
    if (rm < 0 || rm > A[u]) {
        ps("NO");
        exit(0);
    }
    return rm;
}

int main() {
    setIO();
	sc(n);
    FOR (i, 1, n + 1) {
        sc(A[i]);
    }
    if (n == 2) {
        ps(A[1] == A[2] ? "YES" : "NO");
        return 0;
    }
    F0R (i, n - 1) {
        int x, y;
        sc(x, y);
        add(x, y); add(y, x);
        deg[x]++; deg[y]++;
        if (deg[x] > 1) {
            root = x;
        }
        if (deg[y] > 1) {
            root = y;
        }
    }
    ps(dfs(0, root) ? "NO" : "YES");
	return 0;
}

Measured memory_bytes: 7680