2 1
1 1
2 1
 8 12
-6 2 -3 2 6 -7 1 -5
2 1
5 6
1 6
1 4
8 2
2 7
2 5
8 3
8 4
3 7
7 6
3 1
 10 13
3 4 -3 8 6 4 -5 1 3 -7
9 5
9 2
10 3
1 4
3 5
9 1
6 10
10 4
3 1
2 7
1 6
1 7
7 8
 43 52
-23 -18 -35 21 -12 38 -35 -11 28 -20 27 -5 9 -19 -39 -25 -32 32 -36 28 11 37 1 -25 -22 9 -15 21 25 -39 10 36 -30 -40 22 26 25 -27 -22 -38 -1 18 -13
33 40
31 23
30 26
21 17
6 2
41 19
32 39
32 23
13 14
25 35
31 30
19 32
25 22
34 36
7 40
23 6
40 12
1 3
23 43
36 13
18 33
17 32
7 3
21 34
41 35
20 7
23 1
41 8
25 19
20 29
42 5
40 21
9 37
17 41
30 10
41 18
39 1
20 24
20 4
42 3
20 25
5 16
31 9
42 28
10 11
19 42
31 38
25 2
31 27
17 25
13 15
31 20
 2 1
1 1
1 2
 5 7
4 1 5 3 -1
2 4
5 4
5 2
1 5
1 2
4 1
1 3
 10 12
5 1 1 8 -8 10 -3 -2 1 7
5 3
8 2
10 9
4 6
5 6
4 5
5 10
4 7
8 4
3 1
3 6
6 10
 20 40
-9 -10 -9 15 -3 -5 -17 -10 -6 2 -13 19 10 -15 15 -14 17 0 7 -8
3 17
6 18
15 12
2 5
18 3
16 20
6 17
20 10
10 18
9 12
15 3
6 4
15 16
20 6
20 9
9 4
4 8
14 5
11 7
12 11
3 13
14 19
7 17
16 14
19 7
12 13
14 13
13 11
9 14
13 17
8 19
5 20
2 17
2 16
12 5
8 1
20 3
6 2
5 18
13 8

YES
                                                               1
 NO
 YES
                                                              -7
                                                              10
                                                             -16
                                                               3
                                                              13
                                                               0
                                                               4
                                                               5
                                                               0
                                                              -6
                                                               0
                                                               0
                                                               1
 NO
 YES
                                                               1
 YES
                                                               2
                                                               1
                                                              -1
                                                              -1
                                                               0
                                                               0
                                                               5
 YES
-4
1
1
17
-7
-3
6
-3
-3
5
0
0
 YES
                                                             -30
                                                             -21
                                                             -23
                                                             -10
                                                              21
                                                             -52
                                                               0
                                                               2
                                                               0
                                                              -9
                                                               0
                                                              16
                                                              38
                                                               0
                                                              42
                                                               0
                                                              -1
                                                               7
                                                             -64
                                                              51
                                                               0
                                                               7
                                                              47
                                                               0
                                                               0
                                                               0
                                                              10
                                                               0
                                                             -39
                                                               0
                                                               0
                                                               0
                                                               0
                                                               0
                                                               0
                                                              -9
                                                               0
                                                               0
                                                               0
                                                               0

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using PII = pair<ll, ll>;
template <typename T>
void chmin(T &a, const T &b) {
  a = min(a, b);
}
template <typename T>
void chmax(T &a, const T &b) {
  a = max(a, b);
}
struct FastIO {
  FastIO() {
    cin.tie(0);
    ios::sync_with_stdio(0);
  }
} fastiofastio;
const ll INF = 1LL << 60;
int main(void) {
  ll n, m;
  cin >> n >> m;
  vector<ll> c(n);
  for (ll i = (ll)0; i < (ll)n; ++i) cin >> c[i];
  vector<vector<PII>> g(n);
  for (ll i = (ll)0; i < (ll)m; ++i) {
    ll a, b;
    cin >> a >> b;
    a--, b--;
    g[a].emplace_back(b, i);
    g[b].emplace_back(a, i);
  }
  ll x = -1, y = -1, z = -1;
  vector<ll> ans(m), depth(n, -1);
  function<ll(ll, ll)> dfs = [&](ll v, ll p) {
    ll ret = 0;
    for (auto to : g[v]) {
      if (to.first == p) continue;
      if (depth[to.first] == -1) {
        depth[to.first] = depth[v] + 1;
        ans[to.second] = c[to.first] - dfs(to.first, v);
        ;
        ret += ans[to.second];
      } else if (depth[v] > depth[to.first]) {
        if ((depth[v] - depth[to.first]) % 2 == 0 && x == -1) {
          x = v, y = to.first, z = to.second;
        }
      }
    };
    return ret;
  };
  depth[0] = 0;
  ll ret = dfs(0, -1);
  ;
  ;
  ;
  ;
  if (ret != c[0]) {
    if (x == -1 || (ret - c[0]) % 2) {
      cout << "NO" << endl;
      return 0;
    }
    ll diff;
    if (depth[y] % 2)
      diff = (ret - c[0]) / 2;
    else
      diff = -(ret - c[0]) / 2;
    ;
    ll end_v;
    vector<ll> path;
    vector<bool> used(n);
    function<bool(ll, ll)> getpath = [&](ll v, ll p) {
      ;
      used[v] = true;
      if (v == end_v) return true;
      bool ret = false;
      for (auto to : g[v]) {
        if (to.first == p) continue;
        if (used[to.first]) continue;
        bool tmp = getpath(to.first, v);
        ret |= tmp;
        if (tmp) path.push_back(to.second);
      }
      return ret;
    };
    ans[z] += diff;
    end_v = x;
    getpath(y, -1);
    ;
    for (ll i = (ll)0; i < (ll)path.size(); ++i) {
      if (i % 2 == 0)
        ans[path[i]] -= diff;
      else
        ans[path[i]] += diff;
    }
    end_v = y;
    path.clear();
    used.assign(n, false);
    getpath(0, -1);
    reverse(path.begin(), path.end());
    ;
    for (ll i = (ll)0; i < (ll)path.size(); ++i) {
      if (i % 2 == 0)
        ans[path[i]] -= 2 * diff;
      else
        ans[path[i]] += 2 * diff;
    }
  }
  cout << "YES" << endl;
  for (auto i : ans) cout << i << endl;
  return 0;
}
