1 #include <cstdio>
 2 #include <iostream>
 3 #include <algorithm>
 4 #include <cstring>
 5 using namespace std;
 6 const long long mo=1e9+7;
 7 int n,m,tot,ltot;
 8 char s[100010];
 9 long long ans,f[2010][2010];
10 int main()
11 {
12     freopen("bracket.in","r",stdin);
13     freopen("bracket.out","w",stdout);
14     scanf("%d%d",&n,&m);
15     scanf("%s",s);
16     for (int i=0;i<m;i++)
17     {
18         if (s[i]==‘(‘) tot++; else tot--;
19         if (i==0) ltot=tot; else ltot=min(tot,ltot);
20     }
21     f[0][0]=1;
22     for (int i=1;i<=n-m;i++)
23         for (int j=0;j<=i;j++)
24             if (j==0) f[i][j]=f[i-1][j+1];
25             else f[i][j]=(f[i-1][j-1]+f[i-1][j+1])%mo;
26     for (int i=0;i<=n-m;i++)
27         for (int j=0;j<=i;j++)
28             if (j+tot<=n-m&&j+ltot>=0)
29                 (ans+=f[i][j]*f[n-m-i][j+tot])%=mo;
30     printf("%lld",ans);
31     return 0;
32 }