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;
vector<vector<pair<long long, long long> > > g;
vector<long long> color, cc;
vector<long long> ans;
vector<bool> used;
vector<long long> cycle, edges;
bool dfs(long long v, long long c) {
  color[v] = c;
  for (auto u : g[v]) {
    if (color[u.first] == c) {
      cycle.push_back(u.first);
      cycle.push_back(v);
      edges.push_back(u.second);
      return 1;
    }
    if (!color[u.first]) {
      if (dfs(u.first, 3 - c)) {
        if (cycle.size() == 1 || cycle[0] != cycle.back()) {
          cycle.push_back(v);
          edges.push_back(u.second);
        }
        return 1;
      }
    }
  }
  return 0;
}
long long dfs2(long long v) {
  used[v] = 1;
  for (auto u : g[v]) {
    if (edges.size() && u.second == edges[0]) continue;
    if (!used[u.first]) {
      ans[u.second] += dfs2(u.first);
    }
  }
  long long am = 0;
  for (auto u : g[v]) am += ans[u.second];
  return cc[v] - am;
}
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long n, m;
  cin >> n >> m;
  g.resize(n);
  ans.resize(m, 0);
  used.resize(n, 0);
  color.resize(n, 0);
  cc.resize(n, 0);
  for (long long i = 0; i < n; ++i) cin >> cc[i];
  for (long long i = 0; i < m; ++i) {
    long long u, v;
    cin >> u >> v;
    u--;
    v--;
    g[v].push_back(make_pair(u, i));
    g[u].push_back(make_pair(v, i));
  }
  bool ok = dfs(0, 1);
  if (!ok) {
    long long sum[2] = {0, 0};
    for (long long i = 0; i < n; ++i) sum[color[i] - 1] += cc[i];
    if (sum[0] != sum[1]) {
      cout << "NO\n";
    } else {
      cout << "YES\n";
      dfs2(0);
      for (long long i = 0; i < m; ++i) cout << ans[i] << '\n';
    }
  } else {
    cout << "YES\n";
    long long left = -dfs2(cycle[0]);
    for (long long i = 0; i < (long long)edges.size(); ++i) {
      if (i % 2)
        ans[edges[i]] += left / 2;
      else
        ans[edges[i]] -= left / 2;
    }
    for (long long i = 0; i < m; ++i) cout << ans[i] << '\n';
  }
}
