#include <bits/stdc++.h>
#define endl "\n"
using namespace std;

const int MOD = 1000000007;

int n,m,k;
char a[1<<17];
bool vis[2044][5111][2];
int dp_ans[2044][5111][2];
int s[1<<17],min_s;

int get_dp(int pos, int sum, bool f) {
	if(sum>2000 || sum<0) return 0;
	if(pos>k) {
		if(f==false) {
			if(sum+min_s>=0 && sum+s[m]==0) return 1;
			else return 0;
		}
		else {
			if(sum==0) return 1;
			else return 0;
		}
	}
	if(vis[pos][sum][f]) return dp_ans[pos][sum][f];
	int ans=0;
	ans=(ans+get_dp(pos+1,sum+1,f))%MOD;//Open
	ans=(ans+get_dp(pos+1,sum-1,f))%MOD;//Close
	if(f==false) {
		if(sum+min_s>=0) ans=(ans+get_dp(pos,sum+s[m],1))%MOD;//Skip;
	}
	vis[pos][sum][f]=true;
	dp_ans[pos][sum][f]=ans;
	return ans;
}

int main() {
	cin.tie(NULL);
	ios::sync_with_stdio(0);
	int i;

	cin>>n>>m;
	k=n-m;
	cin>>(a+1);
	for(i=1;i<=m;i++) if(a[i]=='(') s[i]=1; else s[i]=-1;
	for(i=1;i<=m;i++) s[i]+=s[i-1];
	min_s=1000000000;
	for(i=1;i<=m;i++) min_s=min(min_s,s[i]);
	cout<<get_dp(1,0,0)<<endl;

	return 0;
}