#include <bits/stdc++.h>
using namespace std;
const long long N = 100010;
struct edge {
  long long la, b;
  edge(long long la = 0, long long b = 0) : la(la), b(b){};
} con[N << 1];
long long tot = 1, fir[N];
void add(long long from, long long to) {
  con[++tot] = edge(fir[from], to);
  fir[from] = tot;
  con[++tot] = edge(fir[to], from);
  fir[to] = tot;
}
long long c[N], ans[N], n, m, cnt, dep[N], rt, ano, fat[N], up[N], mar[N];
struct data {
  long long a, b, id;
  data(long long a = 0, long long b = 0, long long id = 0)
      : a(a), b(b), id(id) {}
} ed[N];
pair<long long, long long> ext[N];
bool vis[N];
void dfs_init(long long pos, long long fa) {
  fat[pos] = fa;
  vis[pos] = 1;
  dep[pos] = dep[fa] + 1;
  for (long long i = fir[pos]; i; i = con[i].la) {
    if (con[i].b == fa) continue;
    if (vis[con[i].b]) {
      if (pos > con[i].b) ext[++cnt] = pair<long long, long long>(pos, i);
    } else
      dfs_init(con[i].b, pos), up[con[i].b] = (ed[((i) | 1) >> 1].id);
  }
}
long long dfs(long long pos, long long fa) {
  vis[pos] = 1;
  long long now = c[pos];
  for (long long i = fir[pos]; i; i = con[i].la) {
    if (vis[con[i].b]) continue;
    now -= (ans[(ed[((i) | 1) >> 1].id)] = dfs(con[i].b, pos));
  }
  return now;
}
bool ocy(pair<long long, long long> x) {
  long long a = x.first, b = con[x.second].b;
  return (dep[a] + dep[b] + 1) & 1;
}
void print() {
  puts("YES");
  for (long long i = 1; i <= m; ++i) {
    cout << ans[i] << endl;
  }
}
void modify(long long x, long long y) {
  long long k1 = 1, k2 = -1;
  while (dep[x] > dep[y]) {
    mar[up[x]] += k1;
    k1 = -k1;
    x = fat[x];
  }
  while (dep[y] > dep[x]) {
    mar[up[y]] += k2;
    k2 = -k2;
    y = fat[y];
  }
  while (x != y) {
    mar[up[x]] += k1;
    k1 = -k1;
    x = fat[x];
    mar[up[y]] += k2;
    k2 = -k2;
    y = fat[y];
  }
}
signed main() {
  long long a, b;
  cin >> n >> m;
  for (long long i = 1; i <= n; ++i) cin >> c[i];
  for (long long i = 1; i <= m; ++i) {
    cin >> a >> b;
    ed[i] = data(a, b, i);
  }
  random_shuffle(ed + 1, ed + m + 1);
  for (long long i = 1; i <= m; ++i) add(ed[i].a, ed[i].b);
  dfs_init(1, 0);
  for (long long i = 1; i <= cnt; ++i) {
    if (ocy(ext[i])) {
      rt = ext[i].first, ano = con[ext[i].second].b;
      modify(rt, ano);
      mar[(ed[((ext[i].second) | 1) >> 1].id)]++;
      break;
    }
  }
  memset(vis, 0, sizeof vis);
  if (rt) {
    long long uns = dfs(rt, 0) >> 1;
    for (long long i = 1; i <= m; ++i) ans[i] += mar[i] * uns;
    print();
  } else {
    if (dfs(1, 0) != 0)
      puts("NO");
    else
      print();
  }
  return 0;
}
