#include <bits/stdc++.h>
using namespace std;
#define ff first
#define ss second
#define all(a) a.begin(), a.end()
const int N = 2e5;
const int mod = 1e9 + 7;
/*
5 5
1 2
1 2
4 3
2 3
4 5
2
4 5
1 3
*/
signed main(){
int n, m; cin >> n >> m;
vector<int> g[n+1];
vector<pair<int, int> > edge;
for(int i = 1;i <= m; i++){
int a, b; cin >> a >> b;
edge.push_back({a, b});
g[a].push_back(b);
g[b].push_back(a);
}
int q; cin >> q;
vector<pair<int, int> > Q(q);
for(int i = 0;i < q; i++){
cin >> Q[i].ff >> Q[i].ss;
}
vector<int> in(n+1, -1), out(n+1, -1);
vector<char> ans(m, '#');
vector<int> par(n+1);
vector<int> used(n+1, 0);
int timer = 1;
map<pair<int, int>, int> mp;
//cout << "bridges : " << '\n';
function<void(int, int)> bridges=[&](int v, int p){
in[v] = timer;
out[v] = timer++;
par[v] = p;
used[v] = 1;
int flag = 0;
for(int to : g[v]){
if(!used[to]){
bridges(to, v);
out[v] = min(out[v], out[to]);
}else{
if(to == p){
if(flag){
out[v] = min(out[v], in[to]);
}
flag = 1;
}else
out[v] = min(out[v], in[to]);
}
}
if(p != -1 && in[v] == out[v]){
//cout << v << ' ' << p << '\n';
mp[make_pair(min(v, p), max(v, p))] = 1;
}
};
//cout << '\n';
for(int i = 1;i <= n; i++){
if(!used[i]){
bridges(i, -1);
}
}
for(int i = 0;i < m; i++){
auto [a, b] = edge[i];
if(a > b) swap(a, b);
if(!mp.count({a, b})){
ans[i] = 'B';
}
}
vector<int> path, check;
function<void(int, int)> dfs=[&](int v, int finish){
check.push_back(v);
used[v] = 1;
if(v == finish){
path = check;
return;
}
for(int to : g[v]){
if(used[to]) continue;
dfs(to, finish);
}
check.pop_back();
};
set<pair<int, int> > st;
for(auto [a, b] : Q){
path.clear();
check.clear();
for(int i = 1;i <= n; i++) used[i] = 0;
dfs(a, b);
for(int i = 0;i + 1 < (int)path.size(); i++){
st.insert(make_pair(path[i], path[i+1]));
}
}
for(int i = 0;i < m; i++){
if(ans[i] != '#') continue;
if(st.count(edge[i])){
ans[i] = 'R';
}else if(st.count({edge[i].ss, edge[i].ff})){
ans[i] = 'L';
}
}
for(int i = 0;i < m; i++){
if(ans[i] == '#') ans[i] = 'B';
cout << ans[i];
}
return 0;
}
