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 <typename... As>
struct tpl : public std::tuple<As...> {
  using std::tuple<As...>::tuple;
  tpl() {}
  tpl(std::tuple<As...> const& b) { std::tuple<As...>::operator=(b); }
  template <typename T = tuple<As...> >
  typename tuple_element<0, T>::type const& x() const {
    return get<0>(*this);
  }
  template <typename T = tuple<As...> >
  typename tuple_element<0, T>::type& x() {
    return get<0>(*this);
  }
  template <typename T = tuple<As...> >
  typename tuple_element<1, T>::type const& y() const {
    return get<1>(*this);
  }
  template <typename T = tuple<As...> >
  typename tuple_element<1, T>::type& y() {
    return get<1>(*this);
  }
  template <typename T = tuple<As...> >
  typename tuple_element<2, T>::type const& z() const {
    return get<2>(*this);
  }
  template <typename T = tuple<As...> >
  typename tuple_element<2, T>::type& z() {
    return get<2>(*this);
  }
  template <typename T = tuple<As...> >
  typename tuple_element<3, T>::type const& w() const {
    return get<3>(*this);
  }
  template <typename T = tuple<As...> >
  typename tuple_element<3, T>::type& w() {
    return get<3>(*this);
  }
};
using lli = long long int;
using llu = long long unsigned;
using pii = tpl<lli, lli>;
using piii = tpl<lli, lli, lli>;
using piiii = tpl<lli, lli, lli, lli>;
using vi = vector<lli>;
using vii = vector<pii>;
using viii = vector<piii>;
using vvi = vector<vi>;
using vvii = vector<vii>;
using vviii = vector<viii>;
template <class T>
using min_queue = priority_queue<T, vector<T>, greater<T> >;
template <class T>
using max_queue = priority_queue<T>;
template <size_t... I>
struct my_index_sequence {
  using type = my_index_sequence;
  static constexpr array<size_t, sizeof...(I)> value = {{I...}};
};
namespace my_index_sequence_detail {
template <typename I, typename J>
struct concat;
template <size_t... I, size_t... J>
struct concat<my_index_sequence<I...>, my_index_sequence<J...> >
    : my_index_sequence<I..., (sizeof...(I) + J)...> {};
template <size_t N>
struct make_index_sequence
    : concat<typename make_index_sequence<N / 2>::type,
             typename make_index_sequence<N - N / 2>::type>::type {};
template <>
struct make_index_sequence<0> : my_index_sequence<> {};
template <>
struct make_index_sequence<1> : my_index_sequence<0> {};
}  // namespace my_index_sequence_detail
template <class... A>
using my_index_sequence_for =
    typename my_index_sequence_detail::make_index_sequence<sizeof...(A)>::type;
template <class T, size_t... I>
void print_tuple(ostream& s, T const& a, my_index_sequence<I...>) {
  using swallow = int[];
  (void)swallow{0, (void(s << (I == 0 ? "" : ", ") << get<I>(a)), 0)...};
}
template <class T>
ostream& print_collection(ostream& s, T const& a);
template <class... A>
ostream& operator<<(ostream& s, tpl<A...> const& a);
template <class... A>
ostream& operator<<(ostream& s, tuple<A...> const& a);
template <class A, class B>
ostream& operator<<(ostream& s, pair<A, B> const& a);
template <class T, size_t I>
ostream& operator<<(ostream& s, array<T, I> const& a) {
  return print_collection(s, a);
}
template <class T>
ostream& operator<<(ostream& s, vector<T> const& a) {
  return print_collection(s, a);
}
template <class T, class U>
ostream& operator<<(ostream& s, multimap<T, U> const& a) {
  return print_collection(s, a);
}
template <class T>
ostream& operator<<(ostream& s, multiset<T> const& a) {
  return print_collection(s, a);
}
template <class T, class U>
ostream& operator<<(ostream& s, map<T, U> const& a) {
  return print_collection(s, a);
}
template <class T>
ostream& operator<<(ostream& s, set<T> const& a) {
  return print_collection(s, a);
}
template <class T>
ostream& print_collection(ostream& s, T const& a) {
  s << '[';
  for (auto it = begin(a); it != end(a); ++it) {
    s << *it;
    if (it != prev(end(a))) s << " ";
  }
  return s << ']';
}
template <class... A>
ostream& operator<<(ostream& s, tpl<A...> const& a) {
  s << '(';
  print_tuple(s, a, my_index_sequence_for<A...>{});
  return s << ')';
}
template <class... A>
ostream& operator<<(ostream& s, tuple<A...> const& a) {
  s << '(';
  print_tuple(s, a, my_index_sequence_for<A...>{});
  return s << ')';
}
template <class A, class B>
ostream& operator<<(ostream& s, pair<A, B> const& a) {
  return s << "(" << get<0>(a) << ", " << get<1>(a) << ")";
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  lli n, m;
  cin >> n >> m;
  vi C(n);
  for (lli i = 0; i < (lli)(n); ++i) cin >> C[i];
  vi W(m, 0);
  vvii G(n);
  for (lli i = 0; i < (lli)(m); ++i) {
    int u, v;
    cin >> u >> v;
    --u;
    --v;
    G[u].push_back(make_tuple(v, i));
    G[v].push_back(make_tuple(u, i));
  }
  vi E(n);
  vi depth(n);
  function<lli(int, lli)> dfs = [&](int i, lli d) {
    depth[i] = d;
    E[i] = 1;
    lli c = C[i];
    for (auto e_ : G[i]) {
      int j, e;
      tie(j, e) = e_;
      if (!E[j]) {
        lli cj = dfs(j, d + 1);
        c -= cj;
      }
    }
    return c;
  };
  lli r = dfs(0, 0);
  if (r & 1) {
    cout << "NO" << endl;
    return 0;
  }
  for (lli i = 0; i < (lli)(n); ++i)
    for (auto e_ : G[i]) {
      int j, e;
      tie(j, e) = e_;
      if (depth[i] % 2 == depth[j] % 2) {
        W[e] = (depth[i] & 1) ? -r / 2 : r / 2;
        r = 0;
        C[i] -= W[e];
        C[j] -= W[e];
        goto l1;
      }
    }
l1:;
  if (r) {
    cout << "NO" << endl;
    return 0;
  }
  E.assign(n, 0);
  function<void(int)> dfs2 = [&](int i) {
    E[i] = 1;
    for (auto e_ : G[i]) {
      int j, e;
      tie(j, e) = e_;
      if (!E[j]) {
        dfs2(j);
        W[e] = C[j];
        C[j] -= W[e];
        C[i] -= W[e];
      }
    }
  };
  dfs2(0);
  cout << "YES" << endl;
  for (lli i = 0; i < (lli)(m); ++i) {
    cout << W[i] << '\n';
  }
  return 0;
}
