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 MAXN = 100007;
int n, kolor[MAXN];
long long weights[MAXN], kraw[MAXN];
pair<int, int> pre[MAXN];
vector<pair<int, int> > G[MAXN], cykl;
bool odw[MAXN];
int dfs(int v, int kol = 1) {
  kolor[v] = kol;
  for (auto ele : G[v]) {
    int w, ix;
    tie(w, ix) = ele;
    if (w == pre[v].first) continue;
    if (kolor[w] == 0) {
      pre[w] = {v, ix};
      int r = dfs(w, 3 - kol);
      if (r != -1) return r;
    } else if (kolor[w] == kolor[v]) {
      int s = v;
      do {
        cykl.emplace_back(s, pre[s].second);
        s = pre[s].first;
      } while (s != w);
      cykl.push_back({w, ix});
      return w;
    }
  }
  return -1;
}
void foo(int v, int poprz = -1) {
  odw[v] = true;
  for (auto ele : G[v]) {
    int w, ix;
    tie(w, ix) = ele;
    if (!odw[w]) {
      foo(w, ix);
      weights[v] -= kraw[ix];
    }
  }
  if (poprz != -1) {
    kraw[poprz] += weights[v];
    weights[v] = 0;
  }
}
int main() {
  ios_base::sync_with_stdio(0);
  int m;
  cin >> n >> m;
  for (int i = 1; i <= n; i++) cin >> weights[i];
  for (int i = 1; i <= m; i++) {
    int a, b;
    cin >> a >> b;
    G[a].emplace_back(b, i);
    G[b].emplace_back(a, i);
  }
  int c = dfs(1);
  if (c == -1) {
    long long suma[3] = {0};
    for (int i = 1; i <= n; i++) suma[kolor[i]] += weights[i];
    if (suma[1] == suma[2]) {
      cout << "YES\n";
      foo(1);
      for (int i = 1; i <= m; i++) {
        cout << kraw[i] << "\n";
      }
    } else {
      cout << "NO\n";
    }
  } else {
    foo(c);
    rotate(cykl.begin(), cykl.end() - 1, cykl.end());
    for (int i = 0; i < int(cykl.size()); i++) {
      kraw[cykl[i].second] += ((i % 2) ? -1 : 1) * weights[c] / 2;
    }
    cout << "YES\n";
    for (int i = 1; i <= m; i++) {
      cout << kraw[i] << "\n";
    }
  }
  return 0;
}
