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 MAX_N = 1e5 + 5;
int root[MAX_N];
int find(int u) {
  if (root[u] != u) {
    root[u] = find(root[u]);
  }
  return root[u];
}
void merge(int u, int v) {
  u = find(u);
  v = find(v);
  root[u] = v;
}
map<pair<int, int>, int> idx;
set<int> adj[MAX_N];
long long arr[MAX_N];
long long ans[MAX_N];
long long cur[MAX_N];
void add_edge(int u, int v) {
  adj[u].insert(v);
  adj[v].insert(u);
}
int color[MAX_N];
void dfs(int u, int c) {
  color[u] = c;
  for (int nxt : adj[u]) {
    if (color[nxt] == 0) {
      dfs(nxt, -c);
    }
  }
}
vector<int> Q;
void del(int v) {
  int u = *adj[v].begin();
  ans[idx[{u, v}]] = cur[v];
  cur[u] -= cur[v];
  cur[v] -= cur[v];
  adj[v].erase(u);
  adj[u].erase(v);
  if ((int)adj[u].size() == 1) {
    Q.push_back(u);
  }
}
vector<int> cycle;
void find_cycle(int u, int p) {
  cycle.push_back(u);
  for (int nxt : adj[u]) {
    if (nxt != p) {
      if (nxt == cycle[0]) return;
      find_cycle(nxt, u);
      return;
    }
  }
}
int main() {
  ios::sync_with_stdio(false);
  int n, m;
  cin >> n >> m;
  for (int i = 1; i <= n; i++) {
    cin >> arr[i];
    cur[i] = arr[i];
    root[i] = i;
  }
  vector<pair<int, int>> edges;
  for (int i = 0; i < m; i++) {
    int u, v;
    cin >> u >> v;
    edges.push_back({u, v});
    idx[make_pair(u, v)] = i;
    idx[make_pair(v, u)] = i;
    if (find(u) != find(v)) {
      merge(u, v);
      add_edge(u, v);
    }
  }
  dfs(1, 1);
  bool oddc = false;
  for (auto e : edges) {
    if (color[e.first] == color[e.second]) {
      add_edge(e.first, e.second);
      oddc = true;
      break;
    }
  }
  for (int i = 1; i <= n; i++) {
    if ((int)adj[i].size() == 1) {
      Q.push_back(i);
    }
  }
  while (!Q.empty()) {
    int u = Q.back();
    Q.pop_back();
    if ((int)adj[u].size() == 1) {
      del(u);
    }
  }
  if (oddc) {
    int root = -1;
    for (int i = 1; i <= n; i++) {
      if (!adj[i].empty()) {
        root = i;
      }
    }
    find_cycle(root, root);
    long long last = 0;
    for (int i = 0; i < (int)cycle.size(); i++) {
      if (i % 2 == 0)
        last += cur[cycle[i]];
      else
        last -= cur[cycle[i]];
    }
    last /= 2;
    ans[idx[{cycle[0], cycle.back()}]] = last;
    for (int i = (int)cycle.size() - 1; i >= 1; i--) {
      long long diff = cur[cycle[i]] - last;
      ans[idx[{cycle[i - 1], cycle[i]}]] = diff;
      last = diff;
    }
  }
  for (auto e : edges) {
    arr[e.first] -= ans[idx[e]];
    arr[e.second] -= ans[idx[e]];
  }
  for (int i = 1; i <= n; i++) {
    if (arr[i] != 0) {
      cout << "NO" << endl;
      return 0;
    }
  }
  cout << "YES" << endl;
  for (int i = 0; i < m; i++) {
    cout << ans[i] << '\n';
  }
}
