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;
int N, M;
signed long long C[101010];
int U[101010], V[101010];
vector<pair<int, int>> E[101010];
signed long long R[101010];
int col[101010];
signed long long P[2];
int tree[101010];
int in[101010];
void dfs(int cur, int c) {
  col[cur] = c;
  P[c] += C[cur];
  for (auto& e : E[cur]) {
    if (col[e.first] == -1) {
      tree[e.second] = 1;
      dfs(e.first, c ^ 1);
    }
  }
}
void solve() {
  int i, j, k, l, r, x, y;
  string s;
  cin >> N >> M;
  for (i = 0; i < (N); i++) cin >> C[i];
  for (i = 0; i < (M); i++) {
    cin >> U[i] >> V[i];
    U[i]--, V[i]--;
    E[U[i]].push_back({V[i], i});
    E[V[i]].push_back({U[i], i});
  }
  memset(col, 0xff, sizeof(col));
  dfs(0, 0);
  if (P[0] != P[1]) {
    for (i = 0; i < (M); i++)
      if (col[U[i]] == col[V[i]]) break;
    if (i == M) return (void)printf("NO\n");
    R[i] = (P[col[U[i]]] - P[col[U[i]] ^ 1]) / 2;
    C[U[i]] -= R[i];
    C[V[i]] -= R[i];
  }
  queue<int> Q;
  for (i = 0; i < (N); i++) {
    for (auto& e : E[i])
      if (tree[e.second]) in[i]++;
    if (in[i] == 1) Q.push(i);
  }
  while (Q.size()) {
    int cur = Q.front();
    Q.pop();
    int id = -1;
    for (auto& e : E[cur])
      if (tree[e.second]) id = e.second;
    if (id >= 0) {
      int op = U[id] + V[id] - cur;
      R[id] = C[cur];
      tree[id] = 0;
      C[cur] = 0;
      C[op] -= R[id];
      in[op]--;
      if (in[op] == 1) Q.push(op);
    }
  }
  cout << "YES" << endl;
  for (i = 0; i < (M); i++) cout << R[i] << endl;
}
int main(int argc, char** argv) {
  string s;
  int i;
  if (argc == 1) ios::sync_with_stdio(false), cin.tie(0);
  for (i = 0; i < (argc - 1); i++) s += argv[i + 1], s += '\n';
  for (i = 0; i < (s.size()); i++) ungetc(s[s.size() - 1 - i], stdin);
  cout.tie(0);
  solve();
  return 0;
}
