#include<bits/stdc++.h>
using namespace std;
int n,m,nm[310][310],b[90010],ans,maxx;
void dfs(int x,int y,int top,int j1,int zh){
    if(top==0){
        ans=max(ans,zh);
    }
    if(x!=n){
       if(nm[x+1][y]==-1){
           dfs(x+1,y,top+1,j1+1,zh-j1-1);
       }
       else{
           if(top!=0)
           dfs(x+1,y,top-1,j1+1,zh+j1+1);
       }
       
    }
    if(y!=m){
       if(nm[x][y+1]==-1){
           dfs(x,y+1,top+1,j1+1,zh-j1-1);
       }
       else{
           if(top!=0)
           dfs(x,y+1,top-1,j1+1,zh+j1+1);
       }
       
    }
}
int main(){
    freopen("copy.in","r",stdin);
    freopen("copy.out","w",stdout);
    cin>>n>>m;
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            char a;
            cin>>a;
            if(a=='('){
                nm[i][j]=-1;
            }
            if(a==')'){
                nm[i][j]=1;
            }
        }
    }
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            ans=0;
            string a1;
            a1+='(';
            if(nm[i][j]='('){
                dfs(i,j,1,1,-1);
            }
            maxx=max(ans,maxx);
        }
    }
    cout<<maxx;
    return 0;
}