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 = 102000;
int n, m, color[maxn], isBipartite = true;
int dfn[maxn], dfs_clock, rt;
long long black, white, ans[maxn], c[maxn];
pair<int, int> fa[maxn];
vector<pair<int, int> > G[maxn];
vector<int> oddCycle;
void dfs0(int u, int col, pair<int, int> faEdge) {
  color[u] = col, dfn[u] = ++dfs_clock;
  if (col == 2)
    black += c[u];
  else
    white += c[u];
  fa[u] = faEdge;
  for (auto [v, id] : G[u])
    if (v != faEdge.first) {
      if (dfn[v]) {
        if (dfn[v] < dfn[u] && color[v] == color[u]) {
          isBipartite = false;
          rt = u;
          int p = u;
          while (p != v) {
            oddCycle.push_back(fa[p].second);
            p = fa[p].first;
          }
          oddCycle.push_back(id);
        }
      } else
        dfs0(v, col ^ 1, {u, id});
    }
}
void dfs(int u, int fath) {
  dfn[u] = ++dfs_clock;
  for (auto [v, id] : G[u])
    if (v != fath && !dfn[v]) {
      dfs(v, u);
      if (c[v]) {
        long long d = c[v];
        c[u] -= d, c[v] -= d, ans[id] += d;
      }
    }
}
int main() {
  scanf("%d%d", &n, &m);
  for (int i = 1; i <= n; ++i) scanf("%lld", &c[i]);
  for (int i = 1; i <= m; ++i) {
    int u, v;
    scanf("%d%d", &u, &v);
    G[u].emplace_back(v, i);
    G[v].emplace_back(u, i);
  }
  dfs0(1, 2, {-1, -1});
  memset(dfn, 0, sizeof dfn);
  dfs_clock = 0;
  if (isBipartite) {
    if (black != white) {
      puts("NO");
      return 0;
    } else
      dfs(1, -1);
  } else {
    dfs(rt, -1);
    assert(c[rt] % 2 == 0);
    long long d = c[rt] / 2, sz = (long long)oddCycle.size();
    for (int i = 0; i < sz; ++i) ans[oddCycle[i]] += d * (i & 1 ? -1 : 1);
  }
  puts("YES");
  for (int i = 1; i <= m; ++i) printf("%lld\n", ans[i]);
  return 0;
}
