1 /*
 2     暴力：也是暴力过了，无语。无向图，两端点都要加度数和点
 3 */
 4 #include <cstdio>
 5 #include <algorithm>
 6 #include <cstring>
 7 #include <vector>
 8 #include <cmath>
 9 using namespace std;
10
11 typedef long long ll;
12 const int MAXN = 2e2 + 10;
13 const int INF = 0x3f3f3f3f;
14 ll a[MAXN];
15 vector<int> G[MAXN];
16 int degree[MAXN];
17
18 int main(void)        //hihoCoder 1179 永恒游戏
19 {
20     // freopen ("C.in", "r", stdin);
21
22     int n, m;
23     while (scanf ("%d%d", &n, &m) == 2)
24     {
25         for (int i=0; i<n; ++i)    scanf ("%lld", &a[i]);
26         for (int i=0; i<n; ++i)    G[i].clear ();
27         memset (degree, 0, sizeof (degree));
28         while (m--)
29         {
30             int u, v;    scanf ("%d%d", &u, &v);
31             degree[u]++;    degree[v]++;
32             G[u].push_back (v);    G[v].push_back (u);
33         }
34
35         bool ok = false;
36         for (int i=1; i<=100001; ++i)
37         {
38             ok = false;
39             for (int j=0; j<n; ++j)
40             {
41                 if (a[j] >= degree[j])
42                 {
43                     for (int k=0; k<G[j].size (); ++k)
44                     {
45                         a[j]--;    a[G[j][k]]++;
46                     }
47                     ok = true;    break;
48                 }
49             }
50             if (!ok)    {printf ("%d\n", i - 1); break;}
51         }
52         if (ok)    puts ("INF");
53     }
54
55     return 0;
56 }