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;
const int N = 1e5 + 5;
int n, m, W[N], PAR[N], depth[N], side[2];
pair<int, int> edge[N];
vector<int> adj[N], e[N], cycle;
map<pair<int, int>, bool> seen;
map<pair<int, int>, int> mp;
bool bipartite = 1, C[N], vis[N];
void dfs(int v) {
  if (PAR[v] == 0) PAR[v] = v;
  vis[v] = 1;
  depth[v] = depth[PAR[v]] + 1;
  side[C[v]] += W[v];
  for (int i : adj[v]) {
    if (!vis[i]) {
      e[v].push_back(i);
      e[i].push_back(v);
      PAR[i] = v;
      C[i] = (!C[v]);
      dfs(i);
    } else {
      if (C[i] == C[v]) bipartite = 0;
      if (cycle.empty() && i != PAR[v] && depth[v] > depth[i] &&
          (depth[v] - depth[i]) % 2 == 0) {
        int j = v;
        while (j != i) {
          cycle.push_back(j);
          j = PAR[j];
        }
        cycle.push_back(i);
      }
    }
  }
}
void dfs2(int v) {
  vis[v] = 1;
  for (int i : e[v]) {
    if (!vis[i]) dfs2(i);
  }
  for (int i : e[v]) {
    if (!seen[{v, i}]) {
      seen[{v, i}] = seen[{i, v}] = 1;
      mp[{v, i}] = mp[{i, v}] = W[v];
      W[i] -= W[v];
      W[v] = 0;
    }
  }
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n >> m;
  for (int i = 1; i <= n; i++) cin >> W[i];
  for (int i = 1; i <= m; i++) {
    cin >> edge[i].first >> edge[i].second;
    adj[edge[i].first].push_back(edge[i].second);
    adj[edge[i].second].push_back(edge[i].first);
  }
  dfs(1);
  memset(vis, 0, sizeof vis);
  if (bipartite) {
    if (side[0] != side[1])
      cout << "NO";
    else {
      cout << "YES\n";
      dfs2(1);
      for (int i = 1; i <= m; i++)
        cout << mp[{edge[i].first, edge[i].second}] << ' ';
    }
  } else {
    cout << "YES\n";
    int start = cycle[0];
    dfs2(start);
    int weight = W[start] / 2;
    mp[{start, cycle[1]}] += weight;
    mp[{start, cycle.back()}] += weight;
    mp[{cycle[1], start}] += weight;
    mp[{cycle.back(), start}] += weight;
    weight *= -1;
    for (int i = 1; i < cycle.size() - 1; i++) {
      mp[{cycle[i], cycle[i + 1]}] += weight;
      mp[{cycle[i + 1], cycle[i]}] += weight;
      weight *= -1;
    }
    for (int i = 1; i <= m; i++)
      cout << mp[{edge[i].first, edge[i].second}] << ' ';
  }
}
