#include <bits/stdc++.h>
#define ll long long
#define all(a) (a).begin(), (a).end()
//#pragma GCC optimize("O3")
//#pragma GCC optimize("Ofast")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#define sz() size()
#define fr first
#define sc second
#define pb push_back
#define er erase
#define in insert
#define pi pair<int,int>
#define pii pair<pair<int,int>,int>
#define mp make_pair
//#define int long long
#define rc(s) return cout<<s,0
#define rcc(s) cout<<s,exit(0)
using namespace std;
const int mod=1e9+7;
const int modp=1999999973;
const int modx=998244353;
int n,m,k,height[100005],comp[100005],grad[100005],val[100005];
char ans[100005];
vector<pair<int,int>>edge,nod[100005];
vector<int>nod2[100005],bridge;
int DFS1(int node,int par,int cnt){
height[node]=height[par]+1;
int res=height[node];
for(auto it:nod[node]){
if(it.second!=cnt){
int x=it.first;
int y=it.second;
if(height[x]){
res=min(res,height[x]);
ans[y]='B';
}
else res=min(res,DFS1(x,node,y));
}
}
if(res<height[node]){
ans[cnt]='B';
nod2[par].push_back(node);
nod2[node].push_back(par);
}
else if(cnt>=1) bridge.push_back(cnt);
return res;
}
void DFS2(int node,int curr){
comp[node]=curr;
for(auto i:nod2[node]) if(comp[i]==0) DFS2(i,curr);
}
int DFS3(int node,int par,int cnt){
height[node]=height[par]+1;
for(auto it:nod[node]){
if(it.first!=par){
grad[node]+=DFS3(it.first,node,it.second);
}
}
if(grad[node]==0) ans[cnt]='B';
else if(grad[node]<0 ^ edge[cnt-1].fr==par) ans[cnt]='L';
else ans[cnt]='R';
return grad[node];
}
int32_t main(){
ios_base::sync_with_stdio(false);cin.tie(0);cerr.tie(0);cout.tie(0);
srand(chrono::steady_clock::now().time_since_epoch().count());
// ifstream cin("input.in");
cin >> n >> m;
for(int i=1;i<=m;i++){
int x,y;
cin >> x >> y;
edge.push_back({x,y});
nod[x].push_back({y,i});
nod[y].push_back({x,i});
}
for(int i=1;i<=n;i++) if(!height[i]) DFS1(i,i,0);
for(int i=1;i<=n;i++) if(comp[i]==0) DFS2(i,i);
for(int i=1;i<=n;i++) nod[i].clear();
for(auto i:bridge){
edge[i-1].fr=comp[edge[i-1].fr];
edge[i-1].sc=comp[edge[i-1].sc];
int x=edge[i-1].fr;
int y=edge[i-1].sc;
nod[x].push_back({y,i});
nod[y].push_back({x,i});
}
cin >> k;
for(int i=1;i<=k;i++){
int x,y;
cin >> x >> y;
x=comp[x];
y=comp[y];
grad[x]++;
grad[y]--;
}
for(int i=1;i<=n;i++) height[i]=0;
for(int i=1;i<=n;i++) if(height[i]==0) DFS3(i,i,0);
for(int i=1;i<=m;i++) cout << ans[i] ;
cout << '\n';
return 0;
}
