#include <bits/stdc++.h>
using namespace std;
#define int long long
#pragma GCC optimize("O3,unroll-loops")
const int maxn = 1e5;
int n, m;
vector<pair<int,int>> adj[maxn+2];
int dsu[maxn+2], val[maxn+2], vis[maxn+2];
int bridge[maxn+2], disc[maxn+2], low[maxn+2], ans[maxn+2];
pair<int,int> road[maxn+2];
int timer = 0;
int fin(int a){
return dsu[a]==a ? a : dsu[a]=fin(dsu[a]);
}
void merg(int a,int b){
a=fin(a); b=fin(b);
if(a!=b) dsu[a]=b;
}
void dfs(int u,int parentEdge){
disc[u] = low[u] = ++timer;
for(auto [v,id] : adj[u]){
if(id == parentEdge) continue;
if(!disc[v]){
dfs(v,id);
low[u] = min(low[u], low[v]);
if(low[v] > disc[u]) bridge[id] = 1;
} else {
low[u] = min(low[u], disc[v]);
}
}
}
void dfs2(int u,int p){
vis[u]=1;
for(auto [v,id]: adj[u]){
if(v==p) continue;
dfs2(v,u);
val[u]+=val[v];
if(val[v]>0){
ans[id] = (road[id].first==u)?2:1;
} else if(val[v]<0){
ans[id] = (road[id].first==u)?1:2;
}
}
}
signed main(){
ios::sync_with_stdio(false);
cin.tie(nullptr);
cin>>n>>m;
for(int i=1;i<=n;i++) dsu[i]=i;
for(int i=1;i<=m;i++){
int u,v; cin>>u>>v;
adj[u].push_back({v,i});
adj[v].push_back({u,i});
road[i]={u,v};
}
for(int i=1;i<=n;i++)
if(!disc[i]) dfs(i,0);
for(int i=1;i<=m;i++)
if(!bridge[i]) merg(road[i].first, road[i].second);
for(int i=1;i<=n;i++) adj[i].clear();
for(int i=1;i<=m;i++)
if(bridge[i]){
int a=fin(road[i].first), b=fin(road[i].second);
adj[a].push_back({b,i});
adj[b].push_back({a,i});
}
int q; cin>>q;
while(q--){
int a,b; cin>>a>>b;
val[fin(a)]++; val[fin(b)]--;
}
for(int i=1;i<=n;i++)
if(fin(i)==i && !vis[i])
dfs2(i,0);
for(int i=1;i<=m;i++){
if(ans[i]==0) cout<<'B';
else if(ans[i]==1) cout<<'R';
else cout<<'L';
}
cout<<"\n";
}
