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 = 100005;
vector<int> g[N];
int a[N], b[N], dep[N];
int par[N], vis[N];
long long ans[N], c[N];
void dfs(int v, int pi, int dep) {
  vis[v] = 1;
  par[v] = pi;
  ::dep[v] = dep;
  for (int ind : g[v]) {
    int u = a[ind] ^ b[ind] ^ v;
    if (ind == pi || vis[u]) continue;
    dfs(u, ind, dep + 1);
  }
}
void dfs2(int v, int pi) {
  vis[v] = 1;
  long long val = c[v];
  for (int ind : g[v]) {
    int u = a[ind] ^ b[ind] ^ v;
    if (!vis[u]) {
      dfs2(u, ind);
      val -= ans[ind];
    }
  }
  ans[pi] = val;
}
inline int common(int x, int y) {
  if (a[x] == a[y]) return a[x];
  if (a[x] == b[y]) return a[x];
  if (b[x] == a[y]) return b[x];
  if (b[x] == b[y]) return b[y];
  assert(false);
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  cout << setprecision(32);
  int n, m;
  cin >> n >> m;
  long long sum = 0;
  for (int i = 1; i <= n; i++) {
    cin >> c[i];
    sum += c[i];
  }
  for (int i = 1; i <= m; i++) {
    cin >> a[i] >> b[i];
    g[a[i]].push_back(i);
    g[b[i]].push_back(i);
  }
  if (sum & 1) {
    cout << "NO\n";
    exit(0);
  }
  memset(vis, 0, sizeof(vis));
  dfs(1, 0, 1);
  bool bipartite = true;
  for (int i = 1; i <= m; i++) {
    if ((dep[a[i]] ^ dep[b[i]]) % 2 == 0) {
      bipartite = false;
      break;
    }
  }
  memset(ans, 0, sizeof(ans));
  if (bipartite) {
    memset(vis, 0, sizeof(vis));
    dfs2(1, 0);
    if (ans[0] != 0) {
      cout << "NO\n";
    } else {
      cout << "YES\n";
      for (int i = 1; i <= m; i++) {
        cout << ans[i] << '\n';
      }
    }
    exit(0);
  }
  vector<int> odd_cycle;
  vector<int> vertices;
  set<int> st;
  for (int i = 1; i <= m; i++) {
    if ((dep[a[i]] ^ dep[b[i]]) % 2 == 0) {
      vector<int> left, right;
      int u = a[i];
      int v = b[i];
      while (u != v) {
        if (dep[u] > dep[v]) {
          left.push_back(par[u]);
          u ^= a[par[u]] ^ b[par[u]];
        } else {
          right.push_back(par[v]);
          v ^= a[par[v]] ^ b[par[v]];
        }
      }
      odd_cycle.push_back(i);
      st.insert(i);
      for (auto x : left) {
        odd_cycle.push_back(x);
        st.insert(x);
      }
      reverse(right.begin(), right.end());
      for (auto x : right) {
        odd_cycle.push_back(x);
        st.insert(x);
      }
      vertices.push_back(common(odd_cycle[0], odd_cycle.back()));
      for (int i = 0; i + 1 < odd_cycle.size(); i++) {
        vertices.push_back(common(odd_cycle[i], odd_cycle[i + 1]));
      }
      break;
    }
  }
  memset(vis, 0, sizeof(vis));
  dfs2(a[odd_cycle[0]], 0);
  for (int v : vertices) {
    for (int ind : g[v]) {
      if (st.find(ind) == st.end()) c[v] -= ans[ind];
    }
  }
  sum = 0;
  for (int i = 0; i < vertices.size(); i++) {
    if (i & 1)
      sum += c[vertices[i]];
    else
      sum -= c[vertices[i]];
  }
  assert(sum % 2 == 0);
  sum >>= 1;
  sum += c[vertices[0]];
  for (int i = 0; i < odd_cycle.size(); i++) {
    ans[odd_cycle[i]] = sum;
    sum = c[vertices[(i + 1) % vertices.size()]] - sum;
  }
  cout << "YES\n";
  for (int i = 1; i <= m; i++) {
    cout << ans[i] << '\n';
  }
  return 0;
}
