#include <bits/stdc++.h>
using namespace std;
const long long N = 1e5 + 9;
vector<pair<long long, long long> > adj[N];
long long a[N], mrk[N], is = 1, root = 1, sum[N], ans[N];
vector<long long> cyc;
pair<long long, long long> par[N];
void DFS1(long long u) {
  for (pair<long long, long long> v : adj[u]) {
    if (!mrk[v.first]) {
      mrk[v.first] = 3 - mrk[u];
      par[v.first] = {u, v.second};
      DFS1(v.first);
    } else if (is && mrk[v.first] == mrk[u]) {
      is = 0, root = u;
      long long x = u;
      while (x != v.first) {
        cyc.push_back(par[x].second);
        x = par[x].first;
      }
      cyc.push_back(v.second);
    }
  }
}
void DFS2(long long u) {
  mrk[u] = 1;
  for (pair<long long, long long> v : adj[u]) {
    if (!mrk[v.first]) {
      DFS2(v.first);
      ans[v.second] = a[v.first] - sum[v.first];
      sum[u] += ans[v.second];
    }
  }
}
int32_t main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  long long n, m;
  cin >> n >> m;
  for (long long i = 1; i <= n; i++) cin >> a[i];
  for (long long i = 0; i < m; i++) {
    long long u, v;
    cin >> u >> v;
    adj[u].push_back({v, i});
    adj[v].push_back({u, i});
  }
  mrk[1] = 1;
  DFS1(1);
  fill(mrk, mrk + N, 0);
  DFS2(root);
  if (is && a[root] != sum[root]) return cout << "NO", 0;
  cout << "YES" << endl;
  if (!is)
    for (long long i = 0, t = 1; i < cyc.size(); i++, t *= -1)
      ans[cyc[i]] += t * (a[root] - sum[root]) / 2;
  for (long long i = 0; i < m; i++) cout << ans[i] << " ";
  return 0;
}
