#include<cstdio>
#include<map>
#include<algorithm>
#include<vector>
using namespace std;

const int N=5e4+5;

int a[N],vis[N];
map<int,int> mp;
vector<int> ans;

int main()
{
    int n;scanf("%d",&n);
    for(int i=1;i<=n;i++)
    {
        int x,y;
        scanf
 
("%d%d",&x,&y);
        mp[x]=mp[y]=i;
    }
    int q;scanf("%d",&q);
    for(int i=1;i<=q;i++)
    {
        scanf("%d",a+i);
        if(mp.count(a[i])) vis[mp[a[i]]]++;
    }
    for(int i=1;i<=q;i++)
        if(vis[mp[a[i]]]!=2)
            ans.push_back(a[i]);
    sort(ans.begin
 
(),ans.end());
    printf("%d\n",ans.size());
    for(int i=0;i<ans.size();i++)
        printf("%05d%c",ans[i]," \n"[i+1==ans.size()]);
    return 0;
}