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 M = 1000000007;
const int MM = 998244353;
template <typename T, typename U>
static inline void amin(T &x, U y) {
  if (y < x) x = y;
}
template <typename T, typename U>
static inline void amax(T &x, U y) {
  if (x < y) x = y;
}
int _runtimeTerror_() {
  int n, m;
  cin >> n >> m;
  vector<int> par_edge(n + 1), par(n + 1), dep(n + 1), vis(n + 1), c(n + 1);
  vector<vector<pair<int, int>>> g(n + 1);
  vector<long long> ans(m + 1, 0);
  for (int i = 1; i <= n; ++i) cin >> c[i];
  for (int i = 1; i <= m; ++i) {
    int x, y;
    cin >> x >> y;
    g[x].push_back({y, i});
    g[y].push_back({x, i});
  }
  vector<array<int, 3>> back;
  vector<long long> cnt(2, 0);
  function<void(int, int)> dfs = [&](int s, int p) {
    vis[s] = true;
    par[s] = p;
    cnt[dep[s] & 1] += c[s];
    for (auto &[j, k] : g[s]) {
      if (!vis[j]) {
        dep[j] = dep[s] + 1;
        par_edge[j] = k;
        dfs(j, s);
      } else if (j != p)
        back.push_back({j, s, k});
    }
  };
  dfs(1, 0);
  for (auto &[u, v, id] : back) {
    if ((dep[u] & 1) == (dep[v] & 1)) {
      if (dep[u] & 1)
        ans[id] = (cnt[1] - cnt[0]) / 2, c[u] -= (cnt[1] - cnt[0]) / 2,
        c[v] -= (cnt[1] - cnt[0]) / 2;
      else
        ans[id] = (cnt[0] - cnt[1]) / 2, c[u] -= (cnt[0] - cnt[1]) / 2,
        c[v] -= (cnt[0] - cnt[1]) / 2;
      cnt[0] = cnt[1];
      break;
    }
  }
  if (cnt[0] != cnt[1]) {
    cout << "NO\n";
    return 0;
  }
  vis.assign(n + 1, false);
  function<int(int, int)> dfs2 = [&](int s, int p) {
    vis[s] = true;
    long long sum = 0;
    for (auto &[j, k] : g[s]) {
      if (!vis[j]) sum += dfs2(j, s);
    }
    ans[par_edge[s]] = c[s] - sum;
    return ans[par_edge[s]];
  };
  assert(dfs2(1, 0) == 0);
  cout << "YES\n";
  for (int i = 1; i <= m; ++i) cout << ans[i] << "\n";
  return 0;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int TESTS = 1;
  while (TESTS--) _runtimeTerror_();
  return 0;
}
