#include <iostream>
#include <bits/stdc++.h>
using namespace std;
const int MAXN = 2e5+5;
int currtime;
int n,m;
int k;
int a[MAXN];
vector<int> v1[MAXN];
int bg[MAXN];
vector<int> v2[MAXN];
int b[MAXN];
int p[MAXN];
int s[MAXN];
int tin[MAXN];
int dist[MAXN];
int low[MAXN];
int sz[MAXN];
int find(int a){
if(p[a] == a){
return a;
}
return p[a] = find(p[a]);
}
void join(int a,int b){
a = find(a);
b = find(b);
if(a==b){
return;
}
if(sz[a]<sz[b]){
swap(a,b);
}
p[b] = a;
sz[a] +=sz[b];
}
void dfs(int curr,int par){
tin[curr] = low[curr] = currtime++;
for(int x:v1[curr]){
int next = curr^a[x]^b[x];
if(!tin[next]){
dfs(next,x);
low[curr] = min(low[curr],low[next]);
if(low[next]>tin[curr]){
bg[x] = 1;
}
}else if(x!=par){
low[curr]=min(low[curr],tin[next]);
}
}
}
void dfs2(int curr,int par){
for(int x:v2[curr]){
int next = curr^a[x]^b[x];
if(next == par){
continue;
}
dist[next] = dist[curr]+1;
dfs2(next,curr);
s[curr]+=s[next];
}
}
int main(){
cin>>n>>m;
for(int i=1;i<=n;i++){
p[i] = i;
}
for(int i=1;i<=m;i++){
cin>>a[i]>>b[i];
v1[a[i]].push_back(i);
v1[b[i]].push_back(i);
}
for(int i=1;i<=n;i++){
if(!tin[i]){
dfs(i,-1);
}
}
for(int i=1;i<=m;i++){
if(!bg[i]){
join(a[i],b[i]);
}
}
for(int i=1;i<=m;i++){
if(!bg[i]){
continue;
}
a[i]= find(a[i]);
b[i] = find(b[i]);
v2[a[i]].push_back(i);
v2[b[i]].push_back(i);
}
cin>>k;
while(k--){
int x,y;
cin>>x>>y;
s[find(x)]++;
s[find(y)]--;
}
for(int i=1;i<=n;i++){
if(p[i] == i && !dist[i]){
dist[i] = 1;
dfs2(i,-1);
}
}
for(int i=1;i<=m;i++){
if(!bg[i]){
cout<<'B';
continue;
}
int node;
if(dist[a[i]]>dist[b[i]]){
node = a[i];
}else{
node = b[i];
}
if(s[node]==0){
cout<<'B';
continue;
}
if((s[node]>0 && node==a[i])||(s[node]<0 && node==b[i])){
cout<<'R';
}else{
cout<<'L';
}
}
}
