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 long long MXN = 1e3 + 10;
const long long MXM = (1LL << 18) + 10;
const long long MX5 = 2e5 + 10;
const long long MX6 = 1e6 + 10;
const long long LOG = 20;
const long long INF = 8e18;
const double eps = 1e-9;
const long long MOD = 1e9 + 7;
long long power(long long a, long long b, long long md) {
  return (!b ? 1
             : (b & 1 ? a * power(a * a % md, b / 2, md) % md
                      : power(a * a % md, b / 2, md) % md));
}
long long bmm(long long a, long long b) {
  return (a % b == 0 ? b : bmm(b, a % b));
}
string base2(long long n) {
  string a = "";
  while (n >= 2) {
    a += (char)(n % 2 + '0');
    n /= 2;
  }
  a += (char)(n + '0');
  reverse((a).begin(), (a).end());
  return a;
}
long long n, m, last, cm;
long long C[MX5], A[MX5], W[5], Ans[MX5];
vector<pair<long long, long long> > G[MX5], E;
bool mark[MX5], vis[MX5], f = 1;
void dfs(long long u, long long c) {
  mark[u] = 1, C[u] = c;
  W[c] += A[u];
  for (auto Pr : G[u]) {
    long long v = Pr.first, id = Pr.second;
    if (mark[v]) {
      if (!c != C[v]) f = 0;
      last = id, cm = c;
    } else {
      dfs(v, !c);
    }
  }
  return;
}
void dfs2(long long u) {
  vis[u] = 1;
  for (auto Pr : G[u]) {
    long long v = Pr.first, id = Pr.second;
    if (!vis[v]) {
      dfs2(v);
      Ans[id] = A[v];
      A[u] -= A[v], A[v] = 0;
    }
  }
  return;
}
int main() {
  cin >> n >> m;
  for (int i = 1; i <= n; i++) cin >> A[i];
  for (int i = 0; i < m; i++) {
    long long u, v;
    cin >> u >> v;
    G[u].push_back({v, i}), G[v].push_back({u, i});
    E.push_back({u, v});
  }
  dfs(1, 0);
  if (!f) {
    long long u = E[last].first, v = E[last].second, val = W[0] - W[1];
    if (val % 2) return cout << "NO" << '\n', 0;
    ;
    if (cm) {
      val = -val;
      W[1] -= val;
    } else {
      W[0] -= val;
    }
    Ans[last] = val / 2, A[u] -= val / 2, A[v] -= val / 2;
  }
  if (W[0] != W[1]) return cout << "NO" << '\n', 0;
  ;
  dfs2(1);
  cout << "YES" << '\n';
  for (int i = 0; i < m; i++) cout << Ans[i] << '\n';
  return 0;
}
