#include<bits/stdc++.h>
using namespace std;
vector<pair<int,int>>adj[200005];
int low[100005];
int in[100005];
int p[100005];
int rt[100005];
int lv[100005];
int pa[20][100005];
int cur=0;
int up[100005];
int down[100005];
int vis[100005];
char ans[100005];
vector<pair<int,int>>tr[100005];
stack<int>s;
map<pair<int,int>,int>mp;
void dfs(int u,int pa,int e){
in[u]=low[u]=++cur;
p[u]=pa;
s.push(u);
for(auto [x,id]:adj[u]){
if(id==e)continue;
if(in[x]==0){
dfs(x,u,id);
low[u]=min(low[u],low[x]);
}else{
low[u]=min(low[u],in[x]);
}
}
//cerr<<"u:"<<u<<" "<<in[u]<<' '<<low[u]<<'\n';
if(low[u]==in[u]){
while(s.top()!=u)rt[s.top()]=u,s.pop();
rt[u]=u;
s.pop();
}
}
void efs(int u,int p){
vis[u]=1;
pa[0][u]=p;
lv[u]=lv[p]+1;
for(int i=1;i<20;i++)pa[i][u]=pa[i-1][pa[i-1][u]];
for(auto x:tr[u])if(x.first!=p)efs(x.first,u);
}
int lca(int a,int b){
if(lv[b]>lv[a])swap(a,b);
for(int i=19;i>=0;i--)if(lv[pa[i][a]]>=lv[b])a=pa[i][a];
//cerr<<"a,b:"<<a<<" "<<b<<"\n";
if(a==b)return a;
for(int i=19;i>=0;i--)if(pa[i][a]!=pa[i][b])a=pa[i][a],b=pa[i][b];
//cerr<<a<<' '<<b<<"\n";
return pa[0][a];
}
void ffs(int u,int p,int id){
vis[u]=1;
for(auto x:tr[u])if(x.first!=p){
ffs(x.first,u,x.second);
up[u]+=up[x.first];
down[u]+=down[x.first];
}
//cerr<<"u:"<<u<<' '<<id<<" "<<up[u]<<" "<<down[u]<<"\n";
if(up[u]){
if(mp[{u,p}])ans[id]='R';
else ans[id]='L';
}else if(down[u]){
if(mp[{u,p}])ans[id]='L';
else ans[id]='R';
}else{
ans[id]='B';
}
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(0);
int n,m;cin>>n>>m;
vector<pair<int,int>>e;
for(int i=1;i<=m;i++){
int a,b;cin>>a>>b;
adj[a].push_back({b,i});
adj[b].push_back({a,i});
e.push_back({a,b});
}
for(int i=1;i<=n;i++)if(in[i]==0)dfs(1,0,-1);
for(int i=1;i<=m;i++){
auto [a,b]=e[i-1];
mp[{rt[a],rt[b]}]=1;
if(rt[a]!=rt[b]){
tr[rt[a]].push_back({rt[b],i});
tr[rt[b]].push_back({rt[a],i});
}
}
for(int i=1;i<=n;i++){
if(vis[rt[i]]==0)efs(rt[i],0);
}
//for(int i=1;i<=n;i++)cerr<<rt[i]<<" ";
//cerr<<"\n";
int p;cin>>p;
for(int i=1;i<=p;i++){
int a,b;cin>>a>>b;
a=rt[a],b=rt[b];
if(a!=b){
up[a]++;
down[b]++;
int c=lca(a,b);
//cerr<<"lca:"<<a<<" "<<b<<" "<<c<<"\n";
up[c]--;
down[c]--;
}
}
for(int i=1;i<=n;i++)vis[i]=0;
for(int i=1;i<=m;i++)ans[i]='B';
for(int i=1;i<=n;i++){
if(vis[rt[i]]==0)ffs(rt[i],0,0);
}
for(int i=1;i<=m;i++)cout<<ans[i];
}
