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;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  int N, M;
  cin >> N >> M;
  vector<ll> C(N);
  for (int i = 0; i < N; ++i) cin >> C[i];
  vector<array<int, 2>> edges(M);
  vector<vector<int>> adj(N);
  for (int i = 0; i < M; ++i) {
    int v, u;
    cin >> v >> u;
    edges[i] = {--v, --u};
    adj[v].emplace_back(i);
    adj[u].emplace_back(i);
  }
  int e = -1;
  vector<int> dist(N, -1);
  vector<vector<int>> tree(N);
  function<void(int)> dfs = [&](int v) {
    for (int i : adj[v]) {
      int u = edges[i][0] ^ edges[i][1] ^ v;
      if (dist[u] >= 0) {
        if ((dist[v] + dist[u] + 1) & 1) e = i;
      } else {
        tree[v].emplace_back(i);
        dist[u] = dist[v] + 1;
        dfs(u);
      }
    }
  };
  dist[0] = 0;
  dfs(0);
  array<ll, 2> sum{};
  for (int i = 0; i < N; ++i) sum[dist[i] & 1] += C[i];
  if (e == -1 && sum[0] != sum[1]) {
    cout << "NO\n";
    return 0;
  }
  vector<ll> ans(M);
  if (e != -1) {
    int v = edges[e][0];
    int u = edges[e][1];
    assert((dist[v] & 1) == (dist[u] & 1));
    int p = dist[v] & 1;
    ans[e] = (sum[p] - sum[p ^ 1]) >> 1;
    C[v] -= ans[e];
    C[u] -= ans[e];
  }
  function<void(int)> solve = [&](int v) {
    for (int i : tree[v]) {
      int u = edges[i][0] ^ edges[i][1] ^ v;
      solve(u);
      ans[i] = C[u];
      C[u] -= ans[i];
      C[v] -= ans[i];
    }
  };
  solve(0);
  cout << "YES\n";
  for (int i = 0; i < M; ++i) {
    cout << ans[i] << "\n";
  }
}
