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 T1, typename T2>
bool Max(T1& a, T2 b) {
  return a < b ? a = b, 1 : 0;
}
template <typename T1, typename T2>
bool Min(T1& a, T2 b) {
  return a > b ? a = b, 1 : 0;
}
const int N = 100001;
vector<pair<int, int> > g[N];
long long a[N];
long long ans[N];
int dep[N];
int vi[N], ct;
int odde, odda, oddb;
long long dfs(int i) {
  vi[i] = ct;
  long long ret = a[i];
  for (auto& e : g[i]) {
    if (vi[e.first] == ct) {
      int t = dep[i] - dep[e.first];
      if (t > 0 && t % 2 == 0) {
        odde = e.second;
        odda = i;
        oddb = e.first;
      }
    } else {
      dep[e.first] = dep[i] + 1;
      ans[e.second] = dfs(e.first);
      ret -= ans[e.second];
    }
  }
  return ret;
}
long long dfs2(int i) {
  vi[i] = ct;
  long long ret = a[i];
  for (auto& e : g[i])
    if (vi[e.first] != ct) {
      ans[e.second] = dfs2(e.first);
      ret -= ans[e.second];
    }
  return ret;
}
bool go(int i) {
  if (vi[i] > 0) return 1;
  ++ct;
  odde = -1;
  long long ret = dfs(i);
  if (ret == 0) return 1;
  if (odde < 0) return 0;
  assert(ret % 2 == 0);
  ret /= 2;
  if (dep[odda] & 1) ret = -ret;
  ans[odde] = ret;
  a[odda] -= ret;
  a[oddb] -= ret;
  ++ct;
  ret = dfs2(i);
  assert(ret == 0);
  return 1;
}
void solve() {
  int n, m, u, v;
  cin >> n >> m;
  for (int i = 1; i <= (int)(n); ++i) cin >> a[i];
  for (int i = 0; i < (int)(m); ++i) {
    cin >> u >> v;
    g[u].push_back({v, i});
    g[v].push_back({u, i});
  }
  for (int i = 1; i <= (int)(n); ++i)
    if (!go(i)) {
      cout << "NO" << '\n';
      return;
    }
  cout << "YES" << '\n';
  for (int i = 0; i < (int)(m); ++i) cout << ans[i] << '\n';
}
void init() {}
int main(void) {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.setf(ios::fixed);
  cout.precision(20);
  init();
  int TC = 1;
  for (int TI = 1; TI <= (int)(TC); ++TI) {
    solve();
  }
  return 0;
}
