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;
void ga(int N, int *A) {
  for (int i(0); i < N; i++) scanf("%d", A + i);
}
vector<pair<int, int> > g[100005], G[100005];
int N, M, a, b, C[100005], D[100005], X[100005], O[100005], E[100005],
    t[100005], R = -1, w, v, l, K[100005], H;
void go(int u) {
  if (~E[u]) go(t[u]), K[l++] = E[u];
}
void clr(int u, int c) {
  X[u] = c;
  for (auto &h : g[u])
    if (!X[h.first])
      E[u] = h.second, t[u] = h.first, G[u].push_back(h),
      G[h.first].push_back({u, h.second}), clr(h.first, -c);
    else if (X[h.first] == c) {
      E[u] = -1;
      if (!~R) R = t[h.first], go(h.first), K[l++] = h.second;
    }
}
int dfs(int u, int p, int I) {
  for (auto &h : G[u])
    if (h.first ^ p) C[u] -= dfs(h.first, u, h.second);
  return O[I] = C[u], C[u];
}
int main(void) {
  scanf("%d%d", &N, &M), ga(N, C), memcpy(D, C, sizeof(D));
  for (int i(0); i < M; i++)
    scanf("%d%d", &a, &b), g[--a].push_back({--b, i}), g[b].push_back({a, i});
  clr(0, 1), H = C[max(R, 0)], a = dfs(max(R, 0), -1, 100005 - 1);
  H = -a;
  if (~R) {
    O[*K] -= H / 2, O[K[1]] -= H / 2;
    for (int k(2); k < l; k++) O[K[k]] += k & 1 ? -H / 2 : H / 2;
  }
  for (int i(0); i < N; i++) {
    for (auto &h : g[i]) D[i] -= O[h.second];
    if (D[i]) return puts("NO");
  }
  puts("YES");
  for (int i(0); i < M; i++) printf("%d\n", O[i]);
  return 0;
}
