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 T>
void dbs(string str, T t) {
  cerr << str << " : " << t << "\n";
}
template <class T, class... S>
void dbs(string str, T t, S... s) {
  int idx = str.find(',');
  cerr << str.substr(0, idx) << " : " << t << ",";
  dbs(str.substr(idx + 1), s...);
}
template <class S, class T>
ostream& operator<<(ostream& os, const pair<S, T>& p) {
  return os << "(" << p.first << ", " << p.second << ")";
}
template <class T>
ostream& operator<<(ostream& os, const vector<T>& p) {
  os << "[ ";
  for (auto& it : p) os << it << " ";
  return os << "]";
}
template <class T>
ostream& operator<<(ostream& os, const set<T>& p) {
  os << "[ ";
  for (auto& it : p) os << it << " ";
  return os << "]";
}
template <class S, class T>
ostream& operator<<(ostream& os, const map<S, T>& p) {
  os << "[ ";
  for (auto& it : p) os << it << " ";
  return os << "]";
}
template <class T>
void prc(T a, T b) {
  cerr << "[";
  for (T i = a; i != b; ++i) {
    if (i != a) cerr << ", ";
    cerr << *i;
  }
  cerr << "]\n";
}
typedef struct {
  int x1, y1;
  int index1;
  long long w;
} edge;
long long c[100010];
vector<int> Adj[100010];
int color[100010];
bool visited[100010];
vector<edge> edges;
bool isBipartite = true;
long long edgeWeight[100010];
vector<int> edgeIndicesVisited;
int parent1[100010];
int edgeUsed[100010];
int dfs_timer = 0;
int corruptEdge = -1;
int source, dest;
void DFS(int u, int p, int edgeIndex = -1) {
  visited[u] = true;
  color[u] = color[p] ^ 1;
  edgeUsed[u] = edgeIndex, parent1[u] = p;
  for (auto edgeIndex : Adj[u]) {
    edge currEdge = edges[edgeIndex];
    if (currEdge.x1 != u) {
      swap(currEdge.x1, currEdge.y1);
    }
    if (visited[currEdge.y1]) {
      if (color[currEdge.y1] == color[u]) {
        isBipartite = false;
        corruptEdge = currEdge.index1;
        source = currEdge.y1, dest = u;
      }
    } else if (!visited[currEdge.y1]) {
      DFS(currEdge.y1, u, currEdge.index1);
    }
  }
}
long long checkPossible(int n) {
  long long answer1 = 0;
  for (int i = (int)(1); i <= (int)(n); i++) {
    if (color[i])
      answer1 += c[i];
    else
      answer1 -= c[i];
  }
  return answer1;
}
void solve(int u, int p, int edgeIndex = -1) {
  visited[u] = true;
  long long sumGathered = 0;
  for (auto edgeIds : Adj[u]) {
    edge currEdge = edges[edgeIds];
    if (currEdge.x1 != u) swap(currEdge.x1, currEdge.y1);
    if (!visited[currEdge.y1]) {
      solve(currEdge.y1, u, currEdge.index1);
      sumGathered += edgeWeight[currEdge.index1];
    }
  }
  if (edgeIndex != -1) edgeWeight[edgeIndex] = c[u] - sumGathered;
}
int main() {
  int n, m;
  cin >> n >> m;
  for (int i = (int)(1); i <= (int)(n); i++) {
    long long temp;
    cin >> temp;
    c[i] = temp;
  }
  for (int i = (int)(1); i <= (int)(m); i++) {
    int a1, b1;
    cin >> a1 >> b1;
    Adj[a1].push_back(int(edges.size())), Adj[b1].push_back(int(edges.size()));
    edges.push_back(edge{a1, b1, i - 1, 0});
  }
  DFS(1, 0);
  for (int i = (int)(1); i <= (int)(n); i++) visited[i] = false;
  if (isBipartite) {
    solve(1, 0);
    long long sum1 = checkPossible(n);
    if (sum1 == 0) {
      cout << "YES"
           << "\n";
      for (int i = (int)(0); i <= (int)(m - 1); i++) {
        cout << edgeWeight[i] << "\n";
      }
    } else {
      cout << "NO\n";
    }
  } else {
    solve(source, 0);
    long long remainSum = 0;
    for (auto edgeId : Adj[dest]) {
      edge currEdge = edges[edgeId];
      remainSum += edgeWeight[currEdge.index1];
    }
    remainSum = c[dest] - remainSum;
    assert(remainSum % 2 == 0);
    remainSum /= 2;
    edgeWeight[corruptEdge] += remainSum;
    while (source != dest) {
      edgeWeight[edgeUsed[source]] -= remainSum;
      remainSum *= -1;
      source = parent1[source];
    }
    cout << "YES"
         << "\n";
    for (int i = (int)(0); i <= (int)(m - 1); i++) {
      cout << edgeWeight[i] << "\n";
    }
  }
  return 0;
}
