#include<bits/stdc++.h>
#define ll long long
#define pii pair<int,int>
#define tiii tuple<int,int,int>
using namespace std;
int LGN = 22;
vector<vector<int>> adj;
vector<int> num, low, scc;
int counter = 0;
int scccounter = 0;
stack<int> S;
vector<char> ans;
vector<pii> edges;
void Tarjan(int v, int p){
num[v] = low[v] = counter++;
S.push(v);
for(auto u : adj[v]){
if(u == p) continue;
if(num[u] == -1){
Tarjan(u,v);
low[v] = min(low[v], low[u]);
}else{
low[v] = min(low[v], num[u]);
}
}
if(num[v] == low[v]){
int u;
do{
u = S.top();S.pop();
scc[u] = scccounter;
}while(v != u);
scccounter++;
}
}
// ----
vector<vector<pii>> adjC;
vector<int> depthC;
vector<vector<int>> jumpC;
vector<pii> par;
void DFS(int v, int p, int d){
depthC[v] = d++;
jumpC[0][v] = p;
for(auto u : adjC[v]){
if(u.first == p) continue;
par[u.first] = {v,u.second};
DFS(u.first,v,d);
}
}
bool search(int v, int p, int t){
if(v == t) return true;
for(auto [u,ind] : adjC[v]){
if(u == p) continue;
if(search(u,v,t)){
if(scc[edges[ind].first] == v){
ans[ind] = 'R';
}
else {
ans[ind] = 'L';
}
return true;
}
}
return false;
}
int main(){
int n,m;
cin >> n >> m;
low = num = scc = vector<int>(n,-1);
adj.resize(n);
edges.resize(m);
map<pii,int> freq;
for(int i = 0; i < m; i++){
int a,b;
cin >> a >> b;
a--;b--;
edges[i] = {a,b};
adj[a].push_back(b);
adj[b].push_back(a);
freq[{min(a,b),max(a,b)}]++;
}
int p;
cin >> p;
vector<pii> req(p);
ans.resize(m);
for(int i = 0; i < p; i++){
int a,b;
cin >> a >> b;
a--;b--;
req[i] = {a,b};
}
for(int i = 0; i < n; i++){
if(num[i] == -1){
Tarjan(i,i);
}
}
adjC.resize(scccounter);
for(int i = 0 ;i < m; i++){
int a,b;
tie(a,b) = edges[i];
if(scc[a] != scc[b]){
adjC[scc[a]].push_back({scc[b],i});
adjC[scc[b]].push_back({scc[a],i});
}
}
for(auto [a,b] : req){
search(scc[a],scc[a],scc[b]);
}
for(int i = 0; i < m; i++){
int a,b;
tie(a,b) = edges[i];
if(ans[i] != 'L' && ans[i] != 'R'){
ans[i] = 'B';
}
if(freq[{min(a,b),max(a,b)}] >= 2){
ans[i] = 'B';
}
}
for(int i = 0; i < m; i++){
cout << ans[i];
}
cout << endl;
}
