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;
template <class c>
struct rge {
  c b, e;
};
template <class c>
rge<c> range(c i, c j) {
  return rge<c>{i, j};
}
template <class c>
auto dud(c* x) -> decltype(cerr << *x, 0);
template <class c>
char dud(...);
struct debug {
  template <class c>
  debug& operator<<(const c&) {
    return *this;
  }
};
const int nax = 1e5 + 5;
int h[nax];
long long should[nax], answer[nax];
bool vis[nax];
vector<pair<int, int>> w[nax];
long long EVEN = 0, ODD = 0;
pair<pair<int, int>, int> spec;
vector<pair<int, int>> children[nax];
void dfs_one(int a) {
  if (h[a] % 2)
    ODD += should[a];
  else
    EVEN += should[a];
  assert(!vis[a]);
  vis[a] = true;
  for (pair<int, int> edge : w[a]) {
    int b = edge.first;
    if (!vis[b]) {
      children[a].push_back(edge);
      h[b] = h[a] + 1;
      dfs_one(b);
    } else if ((h[a] - h[b]) % 2 == 0) {
      spec = make_pair(make_pair(a, b), edge.second);
    }
  }
}
void dfs_two(int a) {
  for (pair<int, int> edge : children[a]) {
    int b = edge.first;
    dfs_two(b);
    answer[edge.second] = should[b];
    should[a] -= should[b];
    should[b] = 0;
  }
}
void NO() {
  puts("NO");
  exit(0);
}
int main() {
  int n, m;
  scanf("%d%d", &n, &m);
  for (int i = 1; i <= n; ++i) scanf("%lld", &should[i]);
  for (int i = 1; i <= m; ++i) {
    int a, b;
    scanf("%d%d", &a, &b);
    w[a].push_back({b, i});
    w[b].push_back({a, i});
  }
  dfs_one(1);
  long long need = EVEN - ODD;
  if (need) {
    if (need % 2 != 0) NO();
    need /= 2;
    debug() << " ["
            << "need"
               ": "
            << (need)
            << "] "
               " ["
            << "spec"
               ": "
            << (spec) << "] ";
    int id = spec.second;
    if (id == 0) NO();
    if (h[spec.first.first] % 2 == 1) need *= -1;
    answer[id] = need;
    should[spec.first.first] -= need;
    should[spec.first.second] -= need;
  }
  dfs_two(1);
  assert(should[1] == 0);
  puts("YES");
  for (int i = 1; i <= m; ++i) printf("%lld\n", answer[i]);
}
