#include <bits/stdc++.h>
using namespace std;
typedef pair<int,int> pii;
int n,m,mark1[100001],mark2[100001],dis[100001],k[100001];
vector<pii> adj[100001];
pii edge[100001];
bool vis[100001],use[100001];
string ans;
void dfs(int x) {
vis[x]=true;
for (auto s : adj[x]) {
if (use[s.second]) continue;
use[s.second]=true;
if (vis[s.first]) {
++mark2[x];
--mark2[s.first];
ans[s.second]='B';
} else {
dfs(s.first);
if (mark2[s.first]) ans[s.second]='B';
else {
if (mark1[s.first]>0) {
if (edge[s.second].first==x) ans[s.second]='L';
else ans[s.second]='R';
} else if (mark1[s.first]<0) {
if (edge[s.second].first==x) ans[s.second]='R';
else ans[s.second]='L';
} else ans[s.second]='B';
}
mark2[x]+=mark2[s.first];
mark1[x]+=mark1[s.first];
}
}
}
int main() {
ios_base::sync_with_stdio(0); cin.tie(0);
cin>>n>>m;
for (int i=0; i<m; ++i) {
int a,b; cin>>a>>b;
ans+=" ";
adj[a].push_back(pii(b,i));
adj[b].push_back(pii(a,i));
edge[i]=pii(a,b);
}
int k; cin>>k;
while (k--) {
int a,b; cin>>a>>b;
mark1[a]++;
mark1[b]--;
}
for (int i=1; i<=n; ++i) if (!vis[i]) dfs(i);
cout<<ans;
}
