#include <iostream>
#include <vector>
#include <map>
using namespace std;
const int N=1e5+10;
pair<int,int> edge[N];
int h[N],lw[N],par[N];
bool vis[N],bri[N];
char dir[N];
vector<pair<int,int>> adj[N];
void dfs(int x,int pid=0)
{
vis[x]=1;
lw[x]=h[x];
for(auto [y,id]:adj[x])
{
if(pid==id)continue;
if(!vis[y])
{
h[y]=h[x]+1;
par[y]=x;
dfs(y,id);
if(lw[y]<h[y])
{
// cout<<"Non bridge "<<id<<endl;
bri[id]=0;
}
lw[x]=min(lw[x],lw[y]);
}
else{
// y is ancestor of x
// cout<<"Edge "<<id<<' '<<x<<' '<<y<<endl;
bri[id]=0;
lw[x]=min(lw[x],h[y]);
}
}
// cout<<"At "<<x<<' '<<h[x]<<' '<<lw[x]<<endl;
}
int main()
{
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n,m;
cin>>n>>m;
for(int j=1;j<=m;j++)
{
int x,y;
cin>>x>>y;
edge[j]={x,y};
adj[x].push_back({y,j});
adj[y].push_back({x,j});
bri[j]=(x!=y);
}
dfs(1);
int p;
cin>>p;
map<pair<int,int>,bool> use;
for(int i=0;i<p;i++)
{
int x,y;
cin>>x>>y;
while(x!=y)
{
if(h[x]>h[y])
{
// edge x to par[x] should be
use[{x,par[x]}]=1;
x=par[x];
}
else{
use[{par[y],y}]=1;
y=par[y];
}
}
}
for(int j=1;j<=m;j++)
{
if(!bri[j])cout<<'B';
else if(use[edge[j]])cout<<'R';
else cout<<'L';
}
cout<<endl;
}
