#include <bits/stdc++.h>
using namespace std;
template <class T>
inline void gmin(T &x, const T &y) {
  if (x > y) x = y;
}
template <class T>
inline void gmax(T &x, const T &y) {
  if (x < y) x = y;
}
const int BufferSize = 1 << 16;
char buffer[BufferSize], *Bufferhead, *Buffertail;
bool Terminal;
inline char Getchar() {
  if (Bufferhead == Buffertail) {
    int l = fread(buffer, 1, BufferSize, stdin);
    if (!l) {
      Terminal = 1;
      return 0;
    }
    Buffertail = (Bufferhead = buffer) + l;
  }
  return *Bufferhead++;
}
template <class T>
inline bool read(T &x) {
  x = 0;
  char c = Getchar(), rev = 0;
  while (c < '0' || c > '9') {
    rev |= c == '-';
    c = Getchar();
    if (Terminal) return 0;
  }
  while (c >= '0' && c <= '9') x = x * 10 + c - '0', c = Getchar();
  if (c == '.') {
    c = Getchar();
    double t = 0.1;
    while (c >= '0' && c <= '9')
      x = x + (c - '0') * t, c = Getchar(), t = t / 10;
  }
  x = rev ? -x : x;
  return 1;
}
template <class T1, class T2>
inline bool read(T1 &x, T2 &y) {
  return read(x) & read(y);
}
template <class T1, class T2, class T3>
inline bool read(T1 &x, T2 &y, T3 &z) {
  return read(x) & read(y) & read(z);
}
template <class T1, class T2, class T3, class T4>
inline bool read(T1 &x, T2 &y, T3 &z, T4 &w) {
  return read(x) & read(y) & read(z) & read(w);
}
inline bool reads(char *x) {
  char c = Getchar();
  while (c < 33 || c > 126) {
    c = Getchar();
    if (Terminal) return 0;
  }
  while (c >= 33 && c <= 126) (*x++) = c, c = Getchar();
  *x = 0;
  return 1;
}
template <class T>
inline void print(T x, const char c = '\n') {
  if (!x) {
    putchar('0');
    putchar(c);
    return;
  }
  if (x < 0) putchar('-'), x = -x;
  int m = 0, a[20];
  while (x) a[m++] = x % 10, x /= 10;
  while (m--) putchar(a[m] + '0');
  putchar(c);
}
const int inf = 0x3f3f3f3f;
const int N = 200005, M = 100005, mod = 1e9 + 7;
template <class T, class S>
inline void ch(T &x, const S y) {
  x = (x + y) % mod;
}
inline int exp(int x, int y, const int mod = ::mod) {
  int ans = 1;
  while (y) {
    if (y & 1) ans = (long long)ans * x % mod;
    x = (long long)x * x % mod;
    y >>= 1;
  }
  return ans;
}
int n, m, tot, fa[N], from[N], dep[N], c[N], cir[N], edg[N];
vector<pair<int, int> > g[N], f[N];
long long res[N], val[N];
bool vis[N];
inline void add(vector<pair<int, int> > *g, int x, int y, int z) {
  g[x].push_back(make_pair(y, z));
  g[y].push_back(make_pair(x, z));
}
inline void findcir(int x) {
  vis[x] = 1;
  for (auto i : g[x]) {
    int y = i.first;
    if (vis[i.first]) {
      if (!tot && dep[y] > dep[x] && !(dep[y] - dep[x] & 1)) {
        cir[++tot] = y, edg[tot] = i.second;
        while (y != x) edg[++tot] = from[y], y = fa[y], cir[tot] = y;
        add(f, x, y, i.second);
      }
      continue;
    }
    add(f, x, y, i.second);
    dep[y] = dep[x] + 1;
    fa[y] = x;
    from[y] = i.second;
    findcir(y);
  }
}
inline long long dfs(int x) {
  long long ret = c[x];
  vis[x] = 1;
  for (auto i : f[x]) {
    int y = i.first;
    if (vis[y]) continue;
    ret -= (res[i.second] = dfs(y));
  }
  return ret;
}
int main() {
  read(n, m);
  for (int i = 1; i <= n; i++) read(c[i]);
  for (int i = 1; i <= m; i++) {
    int x, y;
    read(x, y);
    add(g, x, y, i);
  }
  findcir(1);
  memset(vis, 0, sizeof(vis));
  if (!tot) {
    if (dfs(1)) {
      puts("NO");
      return 0;
    }
    puts("YES");
    for (int i = 1; i <= m; i++) printf("%lld\n", res[i]);
    return 0;
  }
  puts("YES");
  for (int i = 1; i <= tot; i++) vis[cir[i]] = 1;
  long long b = 0;
  for (int i = 1; i <= tot; i++) {
    val[i] = dfs(cir[i]);
    b = val[i] - b;
  }
  res[edg[1]] = b / 2;
  for (int i = 1; i < tot; i++) res[edg[i + 1]] = val[i] - res[edg[i]];
  for (int i = 1; i <= m; i++) printf("%lld\n", res[i]);
  return 0;
}
