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 ll = long long;
using ld = long double;
using namespace std;
const int MAXN = 300001;
vector<pair<int, int>> e[MAXN];
vector<pair<int, int>> e2[MAXN];
int h[MAXN];
ll c[MAXN];
ll c2[MAXN];
ll cc[MAXN];
ll ans[MAXN];
int a[MAXN];
int b[MAXN];
int par[MAXN];
int parid[MAXN];
int upv = -1;
int upu = -1;
int upid = -1;
bool w[MAXN];
bool incyc[MAXN];
void setans(int id, ll val) {
  ans[id] = val;
  c[a[id]] -= val;
  c[b[id]] -= val;
}
bool dfs1(int v, int p, int id, int ch) {
  par[v] = p;
  h[v] = ch;
  parid[v] = id;
  for (auto ed : e[v]) {
    if (!h[ed.first]) {
      e2[v].emplace_back(ed.first, ed.second);
      e2[ed.first].emplace_back(v, ed.second);
      dfs1(ed.first, v, ed.second, ch + 1);
      setans(ed.second, c[ed.first]);
    } else if (h[ed.first] < h[v] && h[ed.first] % 2 == h[v] % 2) {
      upv = v;
      upu = ed.first;
      upid = ed.second;
    }
  }
  return c[v];
}
void dfs2(int v, int p, int block) {
  w[v] = true;
  for (auto ed : e2[v]) {
    if (ed.first != p && ed.first != block && !w[ed.first]) {
      dfs2(ed.first, v, block);
      setans(ed.second, c[ed.first]);
    }
  }
}
int n, m;
void pt() {
  for (int i = 1; i <= n; ++i) {
    if (c[i]) {
      assert(false);
    }
  }
  cout << "YES\n";
  for (int i = 0; i < m; ++i) {
    cout << ans[i] << "\n";
  }
  exit(0);
}
int main() {
  ios_base::sync_with_stdio(false);
  cout.setf(ios::fixed);
  cout.precision(20);
  cout.tie(nullptr);
  cin.tie(nullptr);
  cin >> n >> m;
  for (int i = 1; i <= n; ++i) {
    cin >> c[i];
    c2[i] = c[i];
  }
  for (int i = 0; i < m; ++i) {
    ans[i] = 0;
    cin >> a[i] >> b[i];
    e[a[i]].emplace_back(b[i], i);
    e[b[i]].emplace_back(a[i], i);
  }
  if (!dfs1(1, 1, 1, 1)) {
    pt();
  }
  if (upv == -1) {
    cout << "NO\n";
    return 0;
  }
  fill(ans, ans + m, 0);
  copy(c2 + 1, c2 + n + 1, c + 1);
  vector<int> cyc = {upv};
  vector<int> edid = {upid};
  int cv = upv;
  while (cv != upu) {
    edid.push_back(parid[cv]);
    cv = par[cv];
    cyc.push_back(cv);
  }
  int cs = cyc.size();
  int k = cs / 2;
  auto at = [&](int x) { return cyc[(x + cs) % cs]; };
  auto eat = [&](int x) { return edid[(x + cs) % cs]; };
  for (int i = 0; i < cs; ++i) {
    dfs2(cyc[i], at(i + 1), at(i - 1));
  }
  for (int v : cyc) {
    cc[v] = c[v];
    incyc[v] = true;
  }
  for (int i = 0; i < 1; ++i) {
    ll s = 0;
    for (int v : cyc) {
      s += cc[v];
    }
    s /= 2;
    for (int j = 0; j < k; ++j) {
      s -= cc[at(j * 2 + i + 1)];
    }
    setans(edid[i], s);
  }
  for (int i = 1; i < cs; ++i) {
    setans(edid[i], c[at(i - 1)]);
  }
  pt();
}
