#include <bits/stdc++.h>
using namespace std;
//#define int long long
#define sp << " " <<
#define nl << "\n"
vector<vector<pair<int, int>>> g0, g1;
vector<int> id, low, dfsNum, st;
int dfsTimer = 1;
void tarjan(int u, int parentEdge){
dfsNum[u] = low[u] = dfsTimer++;
st.push_back(u);
for(auto e : g0[u]){
if(e.second==parentEdge) continue;
if(!dfsNum[e.first]) tarjan(e.first, e.second);
low[u] = min(low[u], low[e.first]);
}
if(low[u]==dfsNum[u]){
int v = -1;
while(v!=u){
v = st.back(); st.pop_back();
id[v] = u;
}
}
}
int ans[100000] = {}, dir[100000] = {};
pair<int, int> edges[100000];
void dfs(int u){
dfsNum[u] = -1;
for(auto e : g1[u]){
int v = e.first;
if(dfsNum[v]<0) continue;
dfs(v);
dir[u] += dir[v];
if(dir[v]==0) continue;
if(dir[v]>0 == (id[edges[e.second].first]==u)) ans[e.second] = -1;
else ans[e.second] = 1;
}
}
signed main(){
ios_base::sync_with_stdio(false); cin.tie(nullptr);
int n, m; cin >> n >> m;
g0.resize(n), g1.resize(n);
for(int i=0; i<m; ++i){
cin >> edges[i].first >> edges[i].second;
--edges[i].first, --edges[i].second;
if(edges[i].first == edges[i].second) continue;
g0[edges[i].first].emplace_back(edges[i].second, i);
g0[edges[i].second].emplace_back(edges[i].first, i);
}
dfsNum.assign(n, 0), id.assign(n, -1), low.resize(n);
for(int i=0; i<n; ++i) if(!dfsNum[i]) tarjan(i, -1);
for(int i=0; i<m; ++i){
int x = id[edges[i].first], y = id[edges[i].second];
if(x==y) continue;
g1[x].emplace_back(y, i);
g1[y].emplace_back(x, i);
}
int p; cin >> p;
while(p--){
int x, y; cin >> x >> y;
x = id[x-1], y = id[y-1];
++dir[x]; // up
--dir[y]; // down
}
for(int i=0; i<n; ++i) if(dfsNum[i]>=0) dfs(i);
for(int i=0; i<m; ++i){
char c = 'B';
if(ans[i]<0) c = 'L';
if(ans[i]>0) c = 'R';
cout << c;
}
}
