#include<iostream>
#include<cstdio>
#include<cstring>
#include<vector>
#include<algorithm>
using namespace std;
class node
{
public:
	vector<string> patner;
	vector<string> son;
};
vector<node> fc;
vector<string> a;
vector<string> ans;
int n,m;
bool check;
//*******************************不要浮躁***********************************//
void init()
{
	string data;
	cin>>n;
	for(int i=0;i<n;i++)
	{
		node x;
	    fc.push_back(x);
		cin>>data;
		string temp;
		bool b=0;
		for(int j=0;j<data.length();j++)
		{
			if(data[j]=='=')
			{
				fc[i].patner.push_back(temp);
				temp.clear();
				b=1;
				continue;
			}
			if(data[j]=='+')
			{
				if(b==0)
				    fc[i].patner.push_back(temp);
				else
					fc[i].son.push_back(temp);
				temp.clear();
				continue;
			}
			temp+=data[j];
			if(j==data.length()-1)
			{
				fc[i].son.push_back(temp);
			}
		}
	}
	string temp;
	cin>>m;
	for(int i=0;i<m;i++)
	{
		cin>>temp;
		a.push_back(temp);
	}
}
void work()
{
	for(int i=0;i<n;i++)
	{
		for(int j=0;j<fc[i].patner.size();j++)
		{
			bool b=0;
		    for(int k=0;k<a.size();k++)
		    {
		    	if(a[k]==fc[i].patner[j])
				{
					b=1;
					break;
				}
		    }
			if(!b) goto out;
		}
		for(int j=0;j<fc[i].son.size();j++)
		{
			bool b=0;
			for(int k=0;k<m;k++)
			{
				if(fc[i].son[j]==a[k])
				{
					b=1;
					break;
				}
			}
			if(!b)
			{
				check=1;
			    a.push_back(fc[i].son[j]);
				ans.push_back(fc[i].son[j]);
			}
		}
		out:;
	}
}
void print()
{
	int l=ans.size();
	sort(ans.begin(),ans.end());
	cout<<ans.size()<<endl;
	for(int i=0;i<l;i++)
		cout<<ans[i]<<endl;
}
int main()
{
	freopen("origin.in","r",stdin);
	freopen("origin.out","w",stdout);
	init();
	while(1)
	{
		check=0;
	    work();
		if(!check) break;
	}
	print();
	return 0;
}