#include<bits/stdc++.h>
#define int long long
#define ii pair<int,int>
#define F first
#define S second
#define du long double
using namespace std;
const int N=1e5+100;
vector<int> g[N],g2[N];
set<int> st[N];
int u[N];
int v[N];
int a[N];
bool vis[N];
int tin[N];
int low[N];
int timer;
map<ii,char> mp;
map<ii,bool> bridg;
map<int,int> mp2;
int sz;
void dfs2(int v,int p) {
vis[v] = true;
tin[v] = low[v] = timer++;
bool cnt=0;
for (int to : g[v]) {
if (to == p&&cnt==0){
cnt=1;
continue;
}
if (vis[to]) {
low[v] = min(low[v], tin[to]);
} else {
dfs2(to, v);
low[v] = min(low[v], low[to]);
if (low[to] > tin[v]){
bridg[{v, to}]=1;
bridg[{to, v}]=1;
}
}
}
}
void dfs3(int u,int v)
{
vis[u]=1;
mp2[u]=v;
for(auto x:g[u]){
if(bridg[{u,x}]){
g2[v].push_back(x);
continue;
}
if(vis[x])continue;
dfs3(x,v);
}
}
void dfs(int u,int p)
{
vis[u]=1;
for(auto x:g2[u]){
if(x==p)continue;
dfs(x,u);
}
for(auto x:g2[u]){
if(x==p)continue;
a[u]+=a[x];
if(a[x]==0){
mp[{u,x}]='B';
mp[{x,u}]='B';
}
if(a[x]>0){
mp[{u,x}]='L';
mp[{x,u}]='R';
}
if(a[x]<0){
mp[{u,x}]='R';
mp[{x,u}]='L';
}
}
}
void solve()
{
memset(tin,-1,sizeof(tin));
memset(low,-1,sizeof(low));
int n,m;
cin>>n>>m;
for(int i=1;i<=m;i++){
int a,b;
cin>>a>>b;
g[a].push_back(b);
g[b].push_back(a);
u[i]=a;
v[i]=b;
}
for(int i=1;i<=n;i++){
if(vis[i])continue;
dfs2(i,i);
}
memset(vis,0,sizeof(vis));
for(int i=1;i<=n;i++){
if(vis[i])continue;
dfs3(i,i);
}
for(int i=1;i<=n;i++){
for(auto x:g2[i]){
st[i].insert(mp2[x]);
}
g2[i].clear();
for(auto x:st[i]){
g2[i].push_back(x);
}
}
int p;
cin>>p;
while(p--){
int u,v;
cin>>u>>v;
a[mp2[u]]++;
a[mp2[v]]--;
}
memset(vis,0,sizeof(vis));
for(int i=1;i<=n;i++){
int u=mp2[i];
if(vis[u])continue;
dfs(u,u);
}
/*
for(int i=1;i<=n;i++){
cout<<mp2[i]<<" ";
}
cout<<endl;
for(int i=1;i<=n;i++){
cout<<i<<" : ";
for(auto x:g2[i])cout<<x<<" ";cout<<endl;
}
for(int i=1;i<=n;i++){
cout<<a[i]<<" ";
}
cout<<endl;
*/
for(int i=1;i<=m;i++){
int a=mp2[u[i]];
int b=mp2[v[i]];
if(a==b)mp[{a,a}]='B';
cout<<mp[{a,b}];
}
}
main()
{
int t=1;
// cin>>t;
while(t--)solve();
}
