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;
long long readi() {
  long long input = 0;
  char c = ' ';
  while (c < '-') {
    c = getchar();
  }
  bool negative = false;
  if (c == '-') {
    negative = true;
    c = getchar();
  }
  while (c >= '0') {
    input = 10 * input + (c - '0');
    c = getchar();
  }
  if (negative) {
    input = -input;
  }
  return input;
}
void printi(long long output) {
  if (output == 0) {
    putchar('0');
    return;
  }
  if (output < 0) {
    putchar('-');
    output = -output;
  }
  int aout[20];
  int ilen = 0;
  while (output) {
    aout[ilen] = ((output % 10));
    output /= 10;
    ilen++;
  }
  for (int i = ilen - 1; i >= 0; i--) {
    putchar(aout[i] + '0');
  }
  return;
}
string reads() {
  string input = "";
  char c = ' ';
  while (c <= ' ') {
    c = getchar();
  }
  while (c > ' ') {
    input += c;
    c = getchar();
  }
  return input;
}
int sgn(long long x) {
  if (x < 0) {
    return -1;
  }
  if (x > 0) {
    return 1;
  }
  return 0;
}
long long randomize(long long mod) {
  return ((1 << 30) * rand() + (1 << 15) * rand() + rand()) % mod;
}
const long double PI = 4.0 * atan(1.0);
const long double EPS = 1e-30;
long long normalize(long long x, long long mod) {
  return (((x % mod) + mod) % mod);
}
int N, M;
map<int, int> mp[100010];
vector<int> edge[100010];
long long arr[100010];
long long ans[100010];
bool bipartite = true;
bool seen[100010], color[100010], in[100010];
int parent[100010];
long long pref[100010], suf[100010];
vector<int> cyc, nodes;
long long tot;
void dfs(int u, int par, bool col) {
  if (seen[u]) {
    if (col != color[u]) {
      bipartite = false;
      while (nodes.back() != u) {
        cyc.push_back(nodes.back());
        in[nodes.back()] = true;
        nodes.pop_back();
      }
      in[u] = true;
      cyc.push_back(u);
    }
    return;
  }
  nodes.push_back(u);
  seen[u] = true;
  color[u] = col;
  for (int v : edge[u]) {
    if (v == par) {
      continue;
    }
    dfs(v, u, !col);
    if (!bipartite) {
      return;
    }
  }
  nodes.pop_back();
  return;
}
void solve(int u, int par) {
  if (seen[u]) {
    return;
  }
  seen[u] = true;
  for (int v : edge[u]) {
    if (seen[v]) {
      continue;
    }
    if (v == par) {
      continue;
    }
    solve(v, u);
  }
  if (par == -1) {
    return;
  }
  ans[mp[u][par]] = arr[u];
  arr[par] -= arr[u];
  arr[u] = 0;
  return;
}
int32_t main() {
  ios_base::sync_with_stdio(0);
  srand(time(0));
  if (fopen("cf901d.in", "r")) {
    freopen("cf901d.in", "r", stdin);
    freopen("cf901d.out", "w", stdout);
  }
  cin >> N >> M;
  for (int i = 0; i < N; i++) {
    cin >> arr[i];
  }
  for (int i = 0; i < M; i++) {
    int u, v;
    cin >> u >> v;
    u--;
    v--;
    if (u > v) {
      swap(u, v);
    }
    mp[u][v] = i;
    mp[v][u] = i;
    edge[u].push_back(v);
    edge[v].push_back(u);
  }
  dfs(0, -1, 0);
  for (int i = 0; i < N; i++) {
    seen[i] = false;
  }
  if (bipartite) {
    int net = 0;
    for (int i = 0; i < N; i++) {
      if (color[i]) {
        net += arr[i];
      } else {
        net -= arr[i];
      }
    }
    if (net) {
      cout << "NO\n";
      return 0;
    }
    cout << "YES\n";
    solve(0, -1);
    for (int i = 0; i < M; i++) {
      cout << ans[i] << '\n';
    }
    return 0;
  }
  cout << "YES\n";
  for (int u : cyc) {
    for (int v : edge[u]) {
      if (in[v]) {
        continue;
      }
      solve(v, u);
    }
  }
  pref[0] = 0;
  pref[1] = 0;
  for (int i = 0; i < cyc.size(); i++) {
    int u = cyc[i];
    pref[i + 2] = pref[i] + arr[u];
    tot += arr[u];
  }
  suf[cyc.size() + 1] = 0;
  suf[cyc.size()] = 0;
  for (int i = cyc.size() - 1; i >= 0; i--) {
    int u = cyc[i];
    suf[i] = suf[i + 2] + arr[u];
  }
  tot /= 2;
  cyc.push_back(cyc[0]);
  for (int i = 0; i < cyc.size() - 1; i++) {
    int u = cyc[i], v = cyc[i + 1];
    long long res = tot;
    res -= pref[i + 1];
    res -= suf[i + 2];
    ans[mp[u][v]] += res;
  }
  for (int i = 0; i < M; i++) {
    cout << ans[i] << '\n';
  }
  return 0;
}
