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 maxn = 1e5 + 10;
int n, m;
vector<int> g[maxn];
bool marked[maxn];
int h[maxn];
long long int c[maxn];
long long int ans[maxn];
map<pair<int, int>, int> edge;
int part1 = 0, part2 = 0;
int cycleIndex = -1;
int cycleIndex1 = -1;
int par[maxn];
long long int dfs(int v, int p) {
  marked[v] = true;
  if (h[v] % 2 == 0)
    part1 += c[v];
  else
    part2 += c[v];
  par[v] = p;
  long long int temp = 0;
  for (int u : g[v]) {
    if (!marked[u]) {
      h[u] = h[v] + 1;
      temp += dfs(u, v);
    } else if (u != p) {
      if ((h[v] - h[u]) % 2 == 0 && cycleIndex == -1) {
        cycleIndex = v;
        cycleIndex1 = u;
      }
    }
  }
  if (p != -1) ans[edge[make_pair(v, p)]] = c[v] - temp;
  return c[v] - temp;
}
long long int dfs2(int v, int p) {
  marked[v] = true;
  long long int temp = 0;
  for (int u : g[v]) {
    if (!marked[u]) {
      temp += dfs2(u, v);
    }
  }
  if (p != -1) ans[edge[make_pair(v, p)]] = c[v] - temp;
  return c[v] - temp;
}
int main() {
  cin >> n >> m;
  for (int i = 0; i < n; i++) cin >> c[i];
  for (int i = 0; i < m; i++) {
    int v, u;
    cin >> v >> u;
    v--;
    u--;
    edge[make_pair(v, u)] = i;
    edge[make_pair(u, v)] = i;
    g[v].push_back(u);
    g[u].push_back(v);
  }
  dfs(0, -1);
  if (cycleIndex == -1) {
    if (part1 == part2) {
      cout << "YES" << endl;
      for (int i = 0; i < m; i++) cout << ans[i] << endl;
    } else {
      cout << "NO" << endl;
    }
  } else {
    memset(ans, 0, sizeof ans);
    memset(marked, false, sizeof marked);
    int x = dfs2(cycleIndex, -1);
    x /= 2;
    ans[edge[make_pair(cycleIndex, cycleIndex1)]] += x;
    while (cycleIndex != cycleIndex1) {
      ans[edge[make_pair(cycleIndex, par[cycleIndex])]] += x;
      cycleIndex = par[cycleIndex];
      x = -x;
    }
    cout << "YES" << endl;
    for (int i = 0; i < m; i++) cout << ans[i] << endl;
  }
  return 0;
}
