1 #include <iostream>
 2 #include <cstdio>
 3 #include <set>
 4 using namespace std;
 5 const int MAXN = 2005;
 6 int a[MAXN], b[MAXN], sum[MAXN];
 7 int main()
 8 {
 9     int k, n;
10     set<int> ans;
11     cin >> k >> n;
12     for (int i = 1; i <= k; i++) 
13     {
14         cin >> a[i];
15         sum[i] = sum[i - 1] + a[i];
16     }
17     for (int i = 1; i <= n; i++) cin >> b[i];
18     for (int i = 1; i <= k; i++)
19     {
20         set<int> s;
21         for (int j = 1; j <= k; j++)
22         {
23             if (i == j) continue;
24             s.insert(b[1] - (sum[i] - sum[j]));
25         }
26         bool flg = true;
27         for (int j = 2; j <= n; j++)
28         {
29             if (!s.count(b[j])) { flg = false; break; }
30         }
31         if (flg) ans.insert(b[1] - sum[i]);
32     }
33     cout << ans.size() << endl;
34     return 0;
35 }