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, dep[100010], st[100010][17];
long long c[100010], tc[100010], ans[100010];
vector<pair<int, int> > v[100010];
bool vis[100010];
void dfs1(int np, int fath) {
  vis[np] = 1;
  dep[np] = dep[fath] + 1;
  st[np][0] = fath;
  for (int i = 1; i < 17; i++) st[np][i] = st[st[np][i - 1]][i - 1];
  for (auto &x : v[np]) {
    if (x.first == fath || vis[x.first]) continue;
    dfs1(x.first, np);
    ans[x.second] = tc[x.first];
    tc[np] -= tc[x.first];
    tc[x.first] = 0;
  }
}
inline int lca(int x, int y) {
  if (dep[x] < dep[y]) swap(x, y);
  for (int i = 16; i >= 0; i--)
    if (dep[st[x][i]] >= dep[y]) x = st[x][i];
  if (x == y) return x;
  for (int i = 16; i >= 0; i--)
    if (st[x][i] != st[y][i]) x = st[x][i], y = st[y][i];
  return st[x][0];
}
int s[100010], e[100010];
int main() {
  scanf("%d%d", &n, &m);
  for (int i = 1; i <= n; i++) scanf("%lld", &c[i]), tc[i] = c[i];
  for (int i = 1, ti, tj; i <= m; i++) {
    scanf("%d%d", &ti, &tj);
    s[i] = ti;
    e[i] = tj;
    v[ti].push_back(make_pair(tj, i));
    v[tj].push_back(make_pair(ti, i));
  }
  dfs1(1, 0);
  if (tc[1] == 0) {
    puts("YES");
    for (int i = 1; i <= m; i++) printf("%lld\n", ans[i]);
    return 0;
  }
  bool flag = 1;
  int pos = -1, pv = 0;
  for (int i = 1; i <= m; i++) {
    if ((dep[s[i]] + dep[e[i]] - 2 * dep[lca(s[i], e[i])]) % 2 == 0) {
      flag = 0;
      int vl = tc[1] / 2;
      ans[i] = vl;
      pos = i;
      pv = vl;
      c[s[i]] -= vl;
      c[e[i]] -= vl;
      break;
    }
  }
  if (flag) {
    puts("NO");
    return 0;
  }
  puts("YES");
  memset(vis, 0, sizeof(vis));
  copy(c + 1, c + n + 1, tc + 1);
  dfs1(1, 0);
  if (tc[1]) {
    c[s[pos]] += pv * 2;
    c[e[pos]] += pv * 2;
    ans[pos] = -pv;
    memset(vis, 0, sizeof(vis));
    copy(c + 1, c + n + 1, tc + 1);
    dfs1(1, 0);
  }
  for (int i = 1; i <= m; i++) printf("%lld\n", ans[i]);
  return 0;
}
