#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
#define ll long long
#define pb push_back
typedef pair<ll,ll> pii;
typedef tree<ll, null_type, less<ll>, rb_tree_tag, tree_order_statistics_node_update> indexed_set;
const ll MAXN=1e5+5;
const ll INF= 1e9+10;
vector<vector<ll>>adj(MAXN);
ll dp[MAXN], lvl[MAXN], pr[MAXN], balance[MAXN];
bool bridge[MAXN];
map<pii,vector<ll>>mapi;
ll st=1;
void dfs(ll node){
dp[node]=-1;
for(auto u:adj[node]){
if(lvl[u]==0){//tree edge
lvl[u]=lvl[node]+1;
pr[u]=node;
dfs(u);
balance[node]+=balance[u];
dp[node]+=dp[u];
}else if(lvl[u]>lvl[node]){
dp[node]--;
}else if(lvl[u]<lvl[node]){
dp[node]++;
}
}
if(node==st)return;
if(dp[node]==0){//bridge
bridge[node]=true;
}
}
int main(){
ll n,m,p,i,a,b;
cin>>n>>m;
vector<char>ans(m);
for(i=0;i<m;i++){ans[i]='B';
cin>>a>>b;
//if(a>b)swap(a,b);
mapi[{a,b}].pb(i);
adj[a].pb(b);
adj[b].pb(a);
}
cin>>p;
while(p--){
cin>>a>>b;
balance[a]++;
balance[b]--;
}
for(i=1;i<=n;i++){
if(lvl[i]==0){
st=i;
lvl[i]=1;
dfs(i);
}
}
for(i=1;i<=n;i++){
//cout<<i<<" "<<dp[i]<<" "<<balance[i]<<'\n';
if(bridge[i]==false)continue;
a = pr[i]; b=i;
if(balance[i]>0){
//iterar por mapi[edge] e mapi[-edge]
for(auto u:mapi[{a,b}]){
ans[u]='L';
}
for(auto u:mapi[{b,a}]){
ans[u]='R';
}
}else if(balance[i]<0){
for(auto u:mapi[{a,b}]){
ans[u]='R';
}
for(auto u:mapi[{b,a}]){
ans[u]='L';
}
}else{
for(auto u:mapi[{a,b}]){
ans[u]='B';
}
for(auto u:mapi[{b,a}]){
ans[u]='B';
}
}
}
for(i=0;i<m;i++){
cout<<ans[i];
}cout<<'\n';
return 0;
}
