#pragma GCC optimize("Ofast")
#include<bits/stdc++.h>
using namespace std;
#define pb push_back
#define fi first
#define se second
#define sz(a) (int)(a.size())
#define all(a) a.begin(),a.end()
#define lb lower_bound
#define ub upper_bound
#define owo ios_base::sync_with_stdio(0);cin.tie(0);
#define MOD (ll)(998244353)
#define INF (ll)(1e18)
#define debug(...) fprintf(stderr, __VA_ARGS__),fflush(stderr)
#define time__(d) for(long blockTime = 0; (blockTime == 0 ? (blockTime=clock()) != 0 : false);\
debug("%s time : %.4fs\n", d, (double)(clock() - blockTime) / CLOCKS_PER_SEC))
typedef long long int ll;
typedef long double ld;
typedef pair<ll,ll> PII;
typedef pair<int,int> pii;
typedef vector<vector<int>> vii;
typedef vector<vector<ll>> VII;
ll gcd(ll a,ll b){if(!b)return a;else return gcd(b,a%b);}
const int MAXN = 2e5;
vii adj(MAXN);
vector<set<int>>tadj(MAXN);
vector<int>id(MAXN);
vector<int>tin(MAXN),low(MAXN);
stack<int>stk;
int timer = 0,scc = 0;
void tarjan(int v,int p){
tin[v] = low[v] = ++timer;
stk.push(v);
bool pp = 0;
for(int x:adj[v]){
if(x != p || pp){
if(!tin[x]){
tarjan(x,v);
low[v] = min(low[v],low[x]);
}else{
low[v] = min(low[v],tin[x]);
}
}else pp = 1;
}
if(low[v] == tin[v]){
while(stk.top() != v){
id[stk.top()] = scc;
stk.pop();
}
stk.pop();
id[v] = scc;
scc++;
}
}
vector<int>dep(MAXN),val(MAXN);
void dfs(int v,int u){
for(int x:tadj[v]){
if(x != u){
dep[x] = dep[v]+1;
dfs(x,v);
val[v]+=val[x];
}
}
}
int main()
{
owo
int n,m;
cin>>n>>m;
vector<pii>e;
for(int i=0;i<m;i++){
int v,u;
cin>>v>>u;
adj[v].pb(u);
adj[u].pb(v);
e.pb({v,u});
}
for(int i=1;i<=n;i++){
if(!tin[i])tarjan(i,-1);
}
//for(int i=1;i<=n;i++)cout<<id[i]<<" ";
//cout<<'\n';
for(pii x:e){
if(id[x.fi] == id[x.se])continue;
tadj[id[x.fi]].insert(id[x.se]);
tadj[id[x.se]].insert(id[x.fi]);
}
int p;cin>>p;
while(p--){
int a,b;
cin>>a>>b;
val[id[a]]--;
val[id[b]]++;
}
for(int i=1;i<=n;i++){
if(!dep[id[i]]){
dep[id[i]] = 1;
dfs(id[i],-1);
}
}
for(pii x:e){
int a = id[x.fi];
int b = id[x.se];
if(a == b){cout<<"B";continue;}
if(dep[a] > dep[b]){
if(val[a] <0)cout<<"R";
else if(!val[a])cout<<"B";
else cout<<"L";
}
else{
if(val[b] <0)cout<<"L";
else if(!val[b])cout<<"B";
else cout<<"R";
}
}
}
