#include<cstdio>
#include<algorithm>
#include<cmath>
#include<iostream>
#include<set>
#include<vector>
#include<queue>
#include<stack>
#include<cstring>
#include<cstdlib>
#include<ctime>
#define rep(i,a,b) for(register int i=a;i<=b;++i)
#define rev(i,a,b) for(register int i=a;i>=b;--i)
#define gra(i,u) for(register int i=head[u];i;i=edge[i].nxt)
#define Clear(a) memset(a,0,sizeof(a))
#define yes puts("YES")
#define no puts("NO")
using namespace std;
typedef long long ll;
const int INF(1e9+10);
const ll LLINF(1e18+10);
inline int read()
{
	int s=0,w=1;
	char ch=getchar();
	while(ch<'0'||ch>'9'){if(ch=='-')w=-1;ch=getchar();}
	while(ch>='0'&&ch<='9')s=s*10+(ch-'0'),ch=getchar();
	return s*w;
}
template<typename T>
inline T Min(T x,T y){return x<y?x:y;}
template<typename T>
inline T Max(T x,T y){return x>y?x:y;}
template<typename T>
inline void Swap(T&x,T&y){T t=x;x=y;y=t;return;}
template<typename T>
inline T Abs(T x){return x<0?-x:x;}

const int MAXN(510);
const int MOD(1e9+7);

inline int add(int x,int y){return x+y>=MOD?x+y-MOD:x+y;}
inline int mul(int x,int y){return 1ll*x*y%MOD;}

int n,m;
char s[MAXN];
int f[MAXN][MAXN][6];
inline bool check(int l,int r){return (s[l]=='('||s[l]=='?')&&(s[r]==')'||s[r]=='?');}
/*
f[0]=S
f[1]=(A)
f[2]=AS
f[3]=ASB（包含 f[1]） 
f[4]=SASASASA
f[5]=SAS （包含 f[0]） 
*/

int main()
{
	n=read(),m=read();
	scanf("%s",s+1);
	rep(i,1,n) f[i][i][0]=(s[i]=='*'||s[i]=='?');
	rep(i,1,n) f[i][i][5]=f[i][i][0];
	rep(d,2,n) rep(l,1,n-d+1)
	{
		int r=l+d-1;
		if(f[l][r-1][0]&&(s[r]=='?'||s[r]=='*')&&d<=m) f[l][r][0]=1;
		if(check(l,r)) f[l][r][1]=add(add(f[l+1][r-1][0],f[l+1][r-1][2]),add(f[l+1][r-1][3],f[l+1][r-1][4]));
		rep(k,l,r-1)
		{
			f[l][r][2]=add(f[l][r][2],mul(f[l][k][3],f[k+1][r][0]));
			f[l][r][3]=add(f[l][r][3],mul(add(f[l][k][2],f[l][k][3]),f[k+1][r][1]));
			f[l][r][4]=add(f[l][r][4],mul(add(f[l][k][4],f[l][k][5]),f[k+1][r][1]));
			f[l][r][5]=add(f[l][r][5],mul(f[l][k][4],f[k+1][r][0]));
		}
		f[l][r][3]=add(f[l][r][3],f[l][r][1]);
		f[l][r][5]=add(f[l][r][5],f[l][r][0]);
	} 
	printf("%d\n",f[1][n][3]);
	return 0;
}
/*
Date : 2022/9/16
Author : UperFicial
Start coding at : 16:05
finish debugging at :
*/