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 N = -1;
const int INF = 1.01e9;
int main() {
  int n, m;
  scanf("%d%d", &n, &m);
  vector<long long> c(n);
  for (int i = 0; i < n; i++) {
    scanf("%lld", &c[i]);
  }
  vector<vector<pair<int, int>>> e(n);
  for (int i = 0; i < m; i++) {
    int v, u;
    scanf("%d%d", &v, &u);
    v--;
    u--;
    e[v].push_back({u, i});
    e[u].push_back({v, i});
  }
  vector<int> odd;
  vector<int> color(n, -1);
  int V = -1;
  vector<pair<int, int>> st;
  function<void(int, int, int)> dfs0 = [&](int v, int eid, int cc) {
    st.push_back({v, eid});
    color[v] = cc;
    for (auto x : e[v]) {
      int u = x.first;
      if (color[u] == -1) {
        dfs0(u, x.second, cc ^ 1);
        if (!odd.empty()) return;
      } else {
        if (color[u] != (cc ^ 1)) {
          odd.push_back(x.second);
          for (int j = st.size() - 1; st[j].first != u; j--) {
            odd.push_back(st[j].second);
          }
          V = u;
          return;
        }
      }
    }
    st.pop_back();
  };
  dfs0(0, -1, 0);
  vector<long long> answer(m);
  vector<int> used(n);
  function<void(int)> dfs1 = [&](int v) {
    used[v] = 1;
    for (auto x : e[v]) {
      int u = x.first;
      if (!used[u]) {
        dfs1(u);
        long long y = c[u];
        c[v] -= y;
        c[u] -= y;
        answer[x.second] += y;
      }
    }
  };
  if (V == -1) {
    V = 0;
  }
  dfs1(V);
  if (c[V] != 0) {
    if (odd.empty()) {
      puts("NO");
      return 0;
    }
    assert(c[V] % 2 == 0);
    assert(odd.size() % 2 == 1);
    long long add = c[V] / 2;
    for (int i = 0; i < (int)odd.size(); i++) {
      if (i % 2 == 1) {
        answer[odd[i]] -= add;
      } else {
        answer[odd[i]] += add;
      }
    }
  }
  puts("YES");
  for (auto x : answer) {
    printf("%lld\n", x);
  }
  return 0;
}
