#include<bits/stdc++.h>
#include<iostream>
#include<math.h>
#include<vector>
#include<set>
#include<queue>
#include<algorithm>
#include<cstring>    //for memset
using namespace std;

#define lli                      int long long
#define ull                      unsigned long long
#define ld                       long double
#define pi                       acos(-1)
#define pb                       push_back
#define pbk                      pop_back
#define mp                       make_pair
#define ff                       first
#define ss                       second
#define pii                      pair<int,int>
#define gcd(a,b)                 __gcd(a,b)
#define lcm(a,b)                (a/gcd(a,b))*b
#define READ                     freopen("in.txt","r",stdin);
#define WRITE                    freopen("outer.txt","w",stdout);
//#define sort(t)                  sort(t.begin(),t.end())
#define mem(a,b)                 memset(a,b,sizeof a)
#define sf                       scanf
#define pf                       printf
#define cs(p)                    printf("Case %d: ", ++(p))
#define dist(ax,ay,bx,by)        sqrt((ax-bx)*(ax-bx)+(ay-by)*(ay-by))
#define MM                       100003
#define inf                      10000000000000000+7
#define M                        1000000002
#define MINI                     -1000000003
//const int fx[]={+1,-1,+0,+0};
//const int fy[]={+0,+0,+1,-1};
//const int fx[]={+0,+0,+1,-1,-1,+1,-1,+1};   // Kings Move
//const int fy[]={-1,+1,+0,+0,+1,+1,-1,-1};  // Kings Move

//#define for(i,a,n)    for(int i=a;i<n;i++)
//it=myset.find(20);
//int a[8]= {0,0,-1,1,-1,1,-1,1};
//int b[8]= {-1,1,0,0,-1,1,1  ,-1};
vector<int>v1[100005],v2[100005];
bool vis[100005],vis2[100005];
int y,dis[100005],dis2[100005];

int bfs1(int s,int p)
{
    vis[s]=1;
    queue<int>q;
    q.push(s);
    if(p==1)
    dis[s]=0;
    while(!q.empty())
    {
        int u=q.front();
        q.pop();
        y=u;
        //cout<<u<<endl;
        for(int i=0;i<v1[u].size();i++)
        {
            int r=v1[u][i];
            if(vis[r]==0)
            {
                if(p==1)
                dis[r]=dis[u]+1;
                vis[r]=1;
                q.push(r);
            }
        }
    }
    return y;
}
int bfs2(int s,int p)
{
    vis2[s]=1;
    queue<int>q;
    q.push(s);
    if(p==1)
    dis2[s]=0;
    while(!q.empty())
    {
        int u=q.front();
        q.pop();
        y=u;
        for(int i=0;i<v2[u].size();i++)
        {
            int r=v2[u][i];
            if(vis2[r]==0)
            {
                if(p==1)
                dis2[r]=dis2[u]+1;
                vis2[r]=1;
                q.push(r);
            }
        }
    }
    return y;
}

int main()
{
    int i,j,k,n,u,v,m;
    cin>>n;
    for(i=0;i<n-1;i++)
    {
        cin>>u>>v;
        v1[u].pb(v);
        v1[v].pb(u);
    }
    cin>>m;
    for(i=0;i<m-1;i++)
    {
        cin>>u>>v;
        v2[u].pb(v);
        v2[v].pb(u);
    }
    int ly=bfs1(1,0);
    memset(vis,0,sizeof vis);
    int ly2=bfs1(ly,1);
     int ll=bfs2(1,0);
    memset(vis2,0,sizeof vis2);
    int ll2=bfs2(ll,1);
    int pr1=dis[ly2]+1;
    int pr2=(dis2[ll2]/2)+1;
    if(pr2<pr1)
    cout<<"GGEZ"<<endl;
    else cout<<"FF"<<endl;
}