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;
struct Edge {
  int to, idx;
};
vector<vector<Edge>> adj;
vector<int> side;
vector<Edge> odd_cycle;
vector<Edge> pre;
bool bipartite(int v = 0, int p = -1, int s = 0, int idx = -1) {
  if (p == -1) side.assign(adj.size(), -1);
  if (side[v] >= 0) {
    if (side[v] == s) return true;
    odd_cycle.push_back({p, idx});
    int cur = p;
    do {
      odd_cycle.push_back(pre[cur]);
      cur = pre[cur].to;
    } while (cur != v);
    return false;
  }
  side[v] = s;
  pre[v] = {p, idx};
  for (auto u : adj[v]) {
    if (u.to == p) continue;
    if (!bipartite(u.to, v, s ^ 1, u.idx)) return false;
  }
  return true;
}
vector<long long> weigths;
vector<bool> visited;
vector<int> c;
long long dfs_st(int v, int p = -1, int idx = -1) {
  visited[v] = true;
  long long sum = 0;
  for (auto u : adj[v]) {
    if (u.to == p) continue;
    if (!visited[u.to]) sum += dfs_st(u.to, v, u.idx);
  }
  auto todo = c[v] - sum;
  if (idx >= 0) weigths[idx] = todo;
  return todo;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int n, m;
  cin >> n >> m;
  c.resize(n);
  for (int i = 0; i < n; i++) {
    cin >> c[i];
  }
  adj.resize(n);
  for (int i = 0; i < m; i++) {
    int u, v;
    cin >> u >> v;
    u--, v--;
    adj[u].push_back({v, i});
    adj[v].push_back({u, i});
  }
  weigths.assign(m, 0);
  visited.assign(n, false);
  pre.resize(n);
  if (bipartite()) {
    array<long long, 2> sum = {{0, 0}};
    for (int i = 0; i < n; i++) {
      sum[side[i]] += c[i];
    }
    if (sum[0] == sum[1]) {
      dfs_st(0);
    } else {
      cout << "NO" << '\n';
      return 0;
    }
  } else {
    int start = odd_cycle.back().to;
    auto todo = dfs_st(start) / 2;
    for (auto e : odd_cycle) {
      weigths[e.idx] += todo;
      todo *= -1;
    }
  }
  cout << "YES" << '\n';
  for (auto w : weigths) {
    cout << w << '\n';
  }
}
