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;
struct Edge {
  int src, dst, idx;
};
int main() {
  ios_base::sync_with_stdio(false);
  int n, m;
  cin >> n >> m;
  vector<int64_t> w(n);
  for (int i = 0; i < n; i++) {
    cin >> w[i];
  }
  vector<Edge> edges(m);
  vector<vector<Edge> > g(n);
  for (int i = 0; i < m; i++) {
    int a, b;
    cin >> a >> b;
    a--;
    b--;
    edges[i] = {a, b, i};
    g[a].push_back({a, b, i});
    g[b].push_back({b, a, i});
  }
  vector<int64_t> ans(m, 0);
  auto edgify = [&](int eid, int64_t val) {
    ans[eid] += val;
    w[edges[eid].src] -= val;
    w[edges[eid].dst] -= val;
  };
  for (int i = 0; i < m; i++) {
    edgify(i, 1);
  }
  vector<int> color(n, -1);
  vector<pair<int, int> > loop;
  vector<pair<int, int> > stk;
  function<bool(int, int)> dfs = [&](int v, int c) {
    if (color[v] >= 0) {
      if (color[v] == c) {
        return true;
      } else {
        int i = (int)stk.size() - 1;
        do {
          loop.push_back(stk[i]);
          i--;
        } while (i >= 0 && stk[i].first != v);
        return false;
      }
    }
    color[v] = c;
    for (Edge edg : g[v]) {
      stk.emplace_back(edg.dst, edg.idx);
      assert((int)stk.size() <= n + 1);
      bool dfsRes = dfs(edg.dst, c ^ 1);
      stk.pop_back();
      if (!dfsRes) {
        return false;
      }
    }
    return true;
  };
  stk.emplace_back(0, -1);
  bool dfsRes = dfs(0, 0);
  stk.pop_back();
  if (dfsRes) {
    loop.emplace_back(0, -1);
  }
  vector<char> used(n, false);
  for (auto i : loop) {
    used[i.first] = true;
  }
  function<void(int, int, int)> dfs2 = [&](int v, int p, int peid) {
    for (Edge edg : g[v]) {
      if (edg.dst == p || used[edg.dst]) {
        continue;
      }
      used[edg.dst] = true;
      dfs2(edg.dst, v, edg.idx);
    }
    if (peid >= 0) {
      edgify(peid, w[v]);
    }
  };
  for (auto i : loop) {
    dfs2(i.first, -1, -1);
  }
  if (dfsRes) {
    if (w[loop.back().first] != 0) {
      cout << "NO\n";
      return 0;
    }
  } else {
    int64_t soom = 0;
    for (auto i : loop) {
      soom += w[i.first];
    }
    assert(soom % 2 == 0);
    soom /= 2;
    int64_t e0 = soom;
    for (int i = 2; i < (int)loop.size(); i++) {
      e0 -= w[loop[i].first];
    }
    edgify(loop[0].second, e0);
    for (int i = 1; i < (int)loop.size(); i++) {
      edgify(loop[i].second, w[loop[i].first]);
    }
  }
  cout << "YES\n";
  for (int i = 0; i < m; i++) {
    cout << ans[i] << "\n";
  }
  return 0;
}
