#include <bits/stdc++.h>
//#pragma GCC optimize("Ofast")
#define fori(a,b) for(int i=a;i<b;i++)
#define forj(a,b) for(int j=a;j<b;j++)
#define fork(a,b) for(int k=a;k<b;k++)
#define ford(i,a,b) for(int i=a;i>=b;i--)
#define seto(x,i) memset(x,i,sizeof x)
#define inf 0x3f3f3f3f
#define INF 0x3f3f3f3f3f3f3f3f
#define pf first
#define ps second
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
const int N=100010;
int n,m,p,a,b,c,scc,dfn[N],low[N],id[N],inx,dist[N],val[N];
bool ins[N];
stack<int> st;
vector<int> gr[N];
unordered_set<int> cgr[N];
pii edge[N];
void tarjan(int v,int p)
{
dfn[v]=low[v]=++inx;
ins[v]=true; st.push(v);
for(auto i:gr[v])
{
if(i==p)
{
p=-1;
continue;
}
if(!dfn[i])
{
tarjan(i,v);
low[v]=min(low[v],low[i]);
}
else if(ins[i])
low[v]=min(low[v],dfn[i]);
}
if(dfn[v]==low[v])
{
while(st.top()!=v)
{
id[st.top()]=scc;
ins[st.top()]=0;
st.pop();
}
id[st.top()]=scc;
ins[st.top()]=0;
st.pop();
scc++;
}
}
void dfs(int v,int p)
{
for(auto i:cgr[v])
if(i!=p)
{
dist[i]=dist[v]+1;
dfs(i,v);
val[v]+=val[i];
}
}
int main()
{
ios_base::sync_with_stdio(0); cin.tie(0);
cin>>n>>m;
fori(0,m)
{
cin>>edge[i].pf>>edge[i].ps;
gr[edge[i].pf].push_back(edge[i].ps);
gr[edge[i].ps].push_back(edge[i].pf);
}
fori(0,n)
if(!dfn[i])
tarjan(i,-1);
fori(0,m)
if(id[edge[i].pf]!=id[edge[i].ps])
{
cgr[id[edge[i].pf]].insert(id[edge[i].ps]);
cgr[id[edge[i].ps]].insert(id[edge[i].pf]);
}
cin>>p;
fori(0,p)
{
cin>>a>>b;
val[id[a]]++;
val[id[b]]--;
}
fori(0,scc)
if(!dist[i])
dfs(i,-1);
fori(0,m)
{
a=id[edge[i].pf]; b=id[edge[i].ps];
if(a==b)
cout<<"B";
if(dist[a]>dist[b])
{
if(val[a]>0)
cout<<"R";
if(val[a]==0)
cout<<"B";
if(val[a]<0)
cout<<"L";
}
if(dist[a]<dist[b])
{
if(val[b]>0)
cout<<"L";
if(val[b]==0)
cout<<"B";
if(val[b]<0)
cout<<"R";
}
}
return 0;
}
