#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vb = vector<bool>;
using vvb = vector<vb>;
using vi = vector<int>;
using vvi = vector<vi>;
using vl = vector<ll>;
using vvl = vector<vl>;
using vc = vector<char>;
using vvc = vector<vc>;
using vs = vector<string>;
const ll mod = 1e9 + 7,inf = 1e18;
#define pb push_back
#define fast ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
void setIO()
{
fast;
}
int n = 1e5 + 5,m,cmp,TIMER;
vvi adj(n),graph(n);
vb ins(n);
vi dfs_time(n),dfs_low(n),num(n),scc(n),dist(n);
stack<int>s;
void dfs(int u,int p)
{
dfs_low[u] = dfs_time[u] = ++TIMER;
s.push(u);
ins[u] = 1;
for (int v:adj[u]){
if (v == p){p = -1;continue;}
if (!dfs_time[v]){
dfs(v,u);
dfs_low[u] = min(dfs_low[u],dfs_low[v]);
continue;
}
if (ins[v])
dfs_low[u] = min(dfs_low[u],dfs_time[v]);
}
if (dfs_time[u] == dfs_low[u]){
int v = -1;
cmp++;
while (v != u){
v = s.top();
scc[v] = cmp;
ins[v] = 0;
s.pop();
}
}
}
void tree(int u,int p)
{
for (int v:graph[u]){
if (v == p)continue;
dist[v] = dist[u] + 1;
tree(v,u);
num[u] += num[v];
}
//cout<<u<<" "<<num[u]<<endl;
}
int main()
{
setIO();
cin>>n>>m;
vvi edges;
while (m--){
int u,v;
cin>>u>>v;
adj[u].pb(v),adj[v].pb(u);
edges.pb({u,v});
}
for (int i = 1;i<=n;i++)
if (!dfs_time[i])dfs(i,-1);
int q;
cin>>q;
while (q--){
int u,v;
cin>>u>>v;
num[scc[u]]++,num[scc[v]]--;
//cout<<"HERE "<<scc[u]<<" "<<scc[v]<<" "<<num[scc[u]]<<" "<<num[scc[v]]<<endl;
}
for (auto it:edges){
int u = scc[it[0]],v = scc[it[1]];
if (u != v)
graph[u].pb(v),graph[v].pb(u);
}
for (int i = 1;i<=cmp;i++)
if (!dist[i])tree(i,-1);
for (auto it:edges){
int u = scc[it[0]],v = scc[it[1]];
if (dist[u] > dist[v])swap(u,v);
//cout<<u<<" "<<v<<" "<<num[u]<<" "<<num[v]<<endl;
}
for (auto it:edges){
int u = scc[it[0]],v = scc[it[1]];
if (u == v){cout<<"B";continue;}
if (dist[u] > dist[v]){
if (num[u] > 0)cout<<"R";
else if (num[u] == 0)cout<<"B";
else cout<<"L";
}
else{
if (num[v] > 0)cout<<"L";
else if (num[v] == 0)cout<<"B";
else cout<<"R";
}
}
return 0;
}
