#include <bits/stdc++.h>
using namespace std;
const long long MX=1e5+10;
vector < pair < long long , long long > > mas[MX];
map < pair < long long , long long > , long long > reb;
pair < long long , long long > rb[MX];
vector < long long > mosty_in;
long long real_mosty[MX];
long long tin[MX],tou[MX];
long long timer=0;
void CNTMOST(long long zar,long long mun)
{
timer++;
tin[zar]=timer;
tou[zar]=timer;
for(auto u:mas[zar])
{
if(mun==u.first)
{
continue;
}
if(tin[u.first]==0)
{
CNTMOST(u.first,zar);
tou[zar]=min(tou[zar],tou[u.first]);
if(tou[u.first]>tin[zar])
{
mosty_in.push_back(u.second);
}
}
else
{
tou[zar]=min(tou[zar],tin[u.first]);
}
}
return;
}
long long vis[MX];
long long tmm=0;
void DFS(long long zar)
{
vis[zar]=tmm;
for(auto u:mas[zar])
{
if(!vis[u.first] && real_mosty[u.second]==0)
{
DFS(u.first);
}
}
return;
}
long long prfs[MX];
long long vis2[MX];
map < pair < long long , long long > , long long > res2;
void DFS2(long long zar,long long mun)
{
vis2[zar]=1;
for(auto u:mas[zar])
{
if(u.first!=mun)
{
DFS2(u.first,zar);
prfs[zar]+=prfs[u.first];
}
}
if(prfs[zar]!=0)
{
if(prfs[zar]>0)
{
res2[{zar,mun}]=1;
}
else
{
res2[{mun,zar}]=1;
}
}
return;
}
int main()
{
cin.tie(0);
ios_base::sync_with_stdio(0);
long long n,m;
cin>>n>>m;
for(long long i=1;i<=m;i++)
{
cin>>rb[i].first>>rb[i].second;
if(rb[i].first!=rb[i].second)
{
if(reb.find({rb[i].first,rb[i].second})==reb.end())
{
mas[rb[i].first].push_back({rb[i].second,i});
mas[rb[i].second].push_back({rb[i].first,i});
}
}
reb[{rb[i].first,rb[i].second}]++;
reb[{rb[i].second,rb[i].first}]++;
}
for(long long i=1;i<=n;i++)
{
if(tin[i]==0)
{
CNTMOST(i,0);
}
}
for(auto u:mosty_in)
{
if(reb[{rb[u].first,rb[u].second}]==1)
{
real_mosty[u]=1;
}
}
for(long long i=1;i<=n;i++)
{
if(!vis[i])
{
tmm++;
DFS(i);
}
}
for(long long i=1;i<=n;i++)
{
mas[i].clear();
}
for(long long i=1;i<=m;i++)
{
if(real_mosty[i])
{
mas[vis[rb[i].first]].push_back({vis[rb[i].second],i});
mas[vis[rb[i].second]].push_back({vis[rb[i].first],i});
}
}
long long q;
cin>>q;
long long a,b;
while(q--)
{
cin>>a>>b;
prfs[vis[a]]++;
prfs[vis[b]]--;
}
for(long long i=1;i<=n;i++)
{
if(vis2[i]==0)
{
DFS2(i,0);
}
}
for(long long i=1;i<=m;i++)
{
if(!real_mosty[i])
{
cout<<"B";
continue;
}
if(res2.find({vis[rb[i].first],vis[rb[i].second]})!=res2.end())
{
cout<<"R";
continue;
}
if(res2.find({vis[rb[i].second],vis[rb[i].first]})!=res2.end())
{
cout<<"L";
}
else
{
cout<<"B";
}
}
cout<<"\n";
return 0;
}
