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 INF = 1 << 30;
const long long int MAX = 1e9 + 7;
void array_show(int *array, int array_n, char middle = ' ') {
  for (int i = 0; i < array_n; i++)
    printf("%d%c", array[i], (i != array_n - 1 ? middle : '\n'));
}
void array_show(long long int *array, int array_n, char middle = ' ') {
  for (int i = 0; i < array_n; i++)
    printf("%lld%c", array[i], (i != array_n - 1 ? middle : '\n'));
}
void array_show(bool *array, int array_n, char middle = ' ') {
  for (int i = 0; i < array_n; i++)
    printf("%d%c", (array[i] ? 1 : 0), (i != array_n - 1 ? middle : '\n'));
}
void array_show(vector<int> &vec_s, int vec_n = -1, char middle = ' ') {
  if (vec_n == -1) vec_n = vec_s.size();
  for (int i = 0; i < vec_n; i++)
    printf("%d%c", vec_s[i], (i != vec_n - 1 ? middle : '\n'));
}
void array_show(vector<long long int> &vec_s, int vec_n = -1,
                char middle = ' ') {
  if (vec_n == -1) vec_n = vec_s.size();
  for (int i = 0; i < vec_n; i++)
    printf("%lld%c", vec_s[i], (i != vec_n - 1 ? middle : '\n'));
}
int ca[100005];
bool used[100005];
bool color[100005];
vector<pair<int, int> > path[100005];
bool usednext[100005];
int num[100005];
long long int s[100005];
int connect[100005][2];
vector<pair<int, int> > v1, v2;
queue<int> q1;
bool check1(int pos, bool co = true) {
  if (used[pos]) {
    if (color[pos] == co) return true;
    for (int i = v1.size() - 1; i >= 0; i--) {
      v2.push_back(v1[i]);
      usednext[v1[i].second] = true;
      if (v1[i].first == pos) return false;
    }
  }
  used[pos] = true;
  color[pos] = co;
  for (auto a : path[pos]) {
    v1.push_back(make_pair(pos, a.second));
    if (!check1(a.first, !co)) return false;
    v1.pop_back();
  }
  return true;
}
void queue_check() {
  int a, b, c;
  while (!q1.empty()) {
    a = q1.front(), q1.pop();
    for (auto to : path[a]) {
      b = to.first, c = to.second;
      if (!used[c]) {
        used[c] = true;
        s[c] = ca[a], ca[b] -= ca[a], ca[a] = 0;
        a = --num[b];
        if (a == 1) q1.push(b);
        break;
      }
    }
  }
}
int main() {
  int n, m;
  int i, j, k;
  long long int a, b, c;
  bool flag = true;
  cin >> n >> m;
  for (i = 0; i < n; i++) {
    cin >> ca[i];
  }
  for (i = 0; i < m; i++) {
    cin >> a >> b;
    a--, b--;
    path[a].push_back(make_pair(b, i));
    path[b].push_back(make_pair(a, i));
    connect[i][0] = a, connect[i][1] = b;
    num[a]++, num[b]++;
  }
  bool even = check1(0);
  memset(used, false, sizeof(used));
  if (even) {
    a = 0, b = 0;
    for (i = 0; i < n; i++) {
      if (color[i])
        a += ca[i];
      else
        b += ca[i];
    }
    if (a == b)
      cout << "YES" << endl;
    else {
      cout << "NO" << endl;
      return 0;
    }
    for (i = 0; i < n; i++) {
      if (num[i] == 1) q1.push(i);
    }
    queue_check();
    for (i = 0; i < m; i++) {
      if (used[i]) continue;
      used[i] = true;
      s[i] = 1, a = connect[i][0], b = connect[i][1];
      ca[a]--, ca[b]--;
      num[a]--, num[b]--;
      if (num[a] == 1) q1.push(a);
      if (num[b] == 1) q1.push(b);
      queue_check();
    }
    array_show(s, m, '\n');
    return 0;
  }
  cout << "YES" << endl;
  for (i = 0; i < n; i++) {
    if (num[i] == 1) q1.push(i);
  }
  for (i = 0; i < m; i++) {
    if (usednext[i]) used[i] = true;
  }
  queue_check();
  for (i = 0; i < m; i++) {
    if (used[i]) continue;
    used[i] = true;
    s[i] = 1, a = connect[i][0], b = connect[i][1];
    ca[a]--, ca[b]--;
    num[a]--, num[b]--;
    if (num[a] == 1) q1.push(a);
    if (num[b] == 1) q1.push(b);
    queue_check();
  }
  a = 0, b = 0;
  for (i = 0; i < v2.size(); i++) {
    c = v2[i].first;
    a += ca[c];
    if (i % 2 == 1) b += ca[c];
  }
  a = a / 2 - b;
  for (i = 0; i < v2.size(); i++) {
    c = v2[i].second;
    s[c] = a;
    c = v2[i].first;
    a = ca[c] - a;
  }
  array_show(s, m, '\n');
  return 0;
}
