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;
template <typename T>
inline T read(register T& t) {
  register T f = 1;
  register char ch = getchar();
  t = 0;
  while (ch < '0' || ch > '9') {
    if (ch == '-') f = -f;
    ch = getchar();
  }
  while (ch >= '0' && ch <= '9') t = t * 10 + ch - '0', ch = getchar();
  t *= f;
  return t;
}
template <typename T, typename... Args>
inline void read(T& t, Args&... args) {
  read(t);
  read(args...);
}
const long long p = 998244353;
inline long long power(register long long x, register long long k = p - 2) {
  register long long re = 1;
  for (; k; k >>= 1, x = x * x % p)
    if (k & 1) re = re * x % p;
  return re;
}
int n, m;
int head[100005], ne[200005], to[200005], total = 1;
inline void add(int a, int b) {
  total++;
  to[total] = b;
  ne[total] = head[a];
  head[a] = total;
}
long long Ans[200005], c[200005];
bool vis[200005];
int fa[200005], fs[200005];
int deep[200005];
void dfs(int now) {
  if (c[1] == 0) return;
  vis[now] = 1;
  deep[now] = deep[fa[now]] + 1;
  for (int i = head[now]; i; i = ne[i])
    if (vis[to[i]] == 0) {
      fa[to[i]] = now;
      fs[to[i]] = i;
      dfs(to[i]);
    }
  if (fs[now]) {
    Ans[fs[now] >> 1] += c[now];
    c[fa[now]] -= c[now];
    c[now] = 0;
  }
}
void dfs2(int now) {
  if (c[1] == 0) return;
  for (int i = head[now]; i; i = ne[i])
    if (to[i] != fa[now]) {
      if (c[1] == 0) return;
      if (deep[to[i]] < deep[now]) continue;
      if (now != fa[to[i]] && (deep[to[i]] - deep[now]) % 2 == 0) {
        long long qwq = -c[1] / 2;
        if (deep[now] & 1) qwq = c[1] / 2;
        Ans[i >> 1] += qwq;
        int id;
        id = to[i];
        while (id != now) {
          qwq = -qwq;
          Ans[fs[id] >> 1] += qwq;
          id = fa[id];
        }
        qwq = c[1];
        if (deep[now] & 1) qwq = -c[1];
        id = now;
        while (id != 1) {
          Ans[fs[id] >> 1] += qwq;
          qwq = -qwq;
          id = fa[id];
        }
        c[1] = 0;
        return;
      }
      if (now == fa[to[i]]) dfs2(to[i]);
      if (c[1] == 0) return;
    }
}
int main() {
  read(n, m);
  for (int i = 1; i <= n; i++) read(c[i]);
  for (int i = 1, x, y; i <= m; i++) read(x, y), add(x, y), add(y, x);
  dfs(1);
  if (c[1] & 1) return printf("NO\n"), 0;
  dfs2(1);
  if (c[1]) return printf("NO\n"), 0;
  printf("YES\n");
  for (int i = 1; i <= m; i++) printf("%lld\n", Ans[i]);
  return 0;
}
