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;
int N, M;
vector<vector<int> > adj;
vector<int> U, V;
vector<long long> C, W;
vector<int> tin, tout, par, cycle, edge, del, vis;
int timer;
bool dfs(int u, int fe) {
  tin[u] = timer++;
  for (int i = 0; i < adj[u].size(); i++) {
    int e = adj[u][i];
    int v = U[e] + V[e] - u;
    if (e == fe) continue;
    if (tin[v] != -1) {
      if (tout[v] == -1) {
        int t = u;
        while (1) {
          cycle.push_back(t);
          if (t == v) break;
          int pe = par[t];
          t = U[pe] + V[pe] - t;
          edge.push_back(pe);
        }
        edge.push_back(e);
        return true;
      }
      continue;
    }
    par[v] = e;
    if (dfs(v, e)) return true;
  }
  tout[u] = timer;
  return false;
}
void dfs2(int u, int fe) {
  vis[u] = 1;
  for (int i = 0; i < adj[u].size(); i++) {
    int e = adj[u][i];
    int v = U[e] + V[e] - u;
    if (vis[v]) continue;
    if (del[v]) continue;
    dfs2(v, e);
    W[e] = C[v];
    C[u] -= C[v];
  }
}
vector<pair<long long, long long> > sol;
void solve() {
  sol.resize(M);
  sol[edge[0]] = pair<long long, long long>(1, 0);
  for (int i = 1; i < cycle.size(); i++) {
    int u = cycle[i];
    int v = cycle[(i + 1) % cycle.size()];
    int e = edge[i];
    int pe = edge[i - 1];
    sol[e] = pair<long long, long long>(-sol[pe].first, C[u] - sol[pe].second);
  }
  if (sol[edge[0]].first + sol[edge.back()].first == 0) {
    if (sol[edge[0]].second + sol[edge.back()].second != C[cycle[0]]) {
      printf("NO");
      exit(0);
    }
    W[edge[0]] = 0;
  } else {
    if ((C[cycle[0]] - sol[edge[0]].second - sol[edge.back()].second) %
        (sol[edge[0]].first + sol[edge.back()].first)) {
      printf("NO");
      exit(0);
    }
    W[edge[0]] = (C[cycle[0]] - sol[edge[0]].second - sol[edge.back()].second) /
                 (sol[edge[0]].first + sol[edge.back()].first);
  }
  for (int i = 0; i < cycle.size(); i++) {
    W[edge[i]] = W[edge[0]] * sol[edge[i]].first + sol[edge[i]].second;
  }
}
int main() {
  scanf("%d %d", &N, &M);
  C.resize(N);
  for (int i = 0; i < N; i++) {
    scanf("%lld", &C[i]);
  }
  adj.resize(N);
  for (int i = 0; i < M; i++) {
    int u, v;
    scanf("%d %d", &u, &v);
    u--;
    v--;
    adj[u].push_back(U.size());
    adj[v].push_back(U.size());
    U.push_back(u);
    V.push_back(v);
  }
  tin = tout = par = vector<int>(N, -1);
  timer = 0;
  W = vector<long long>(M, 0);
  if (!dfs(0, -1)) {
    vis = vector<int>(N, 0);
    del = vector<int>(N, 0);
    dfs2(0, -1);
    if (C[0]) {
      printf("NO");
    } else {
      printf("YES\n");
      for (int i = 0; i < M; i++) {
        printf("%lld\n", W[i]);
      }
    }
    return 0;
  }
  del = vector<int>(N, 0);
  vis = vector<int>(N, 0);
  for (int i = 0; i < cycle.size(); i++) del[cycle[i]] = 1;
  for (int i = 0; i < cycle.size(); i++) {
    dfs2(cycle[i], -1);
  }
  solve();
  printf("YES\n");
  for (int i = 0; i < M; i++) {
    printf("%lld\n", W[i]);
  }
}
