#include <bits/stdc++.h>
#include <fstream>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#pragma GCC optimize("O2","O3","O1")
#pragma GCC optimize("Ofast")
using namespace std;
ifstream fin("input.txt");
ofstream fout("output.txt");
int t = 0;
int const f = 1e5 + 10;
long long mod = 998244353;
int a[f];
int b[f];
char p[f];
long long dp1[f];
long long dp2[f];
int tr[f];
int cnt =0;
pair<int,int>e[f];
int par[30][f];
pair<int,int> o[f];
int sb[f];
vector<int>g[f];
vector<int>g2[f];
vector<long long> vi;
vector<int>vv[f];
map<pair<int,int>,long long> conv;
// map<long long, long long> cnv;
struct node {
int val;
pair<int,int>frontmin,frontmax,backmin,backmax;
node(){
val =0;
frontmax = frontmin=backmin=backmax ={-1,-1};
}
};
bool B[f];
bool F[f];
// node segtree[f * 4];
// long long fen[f];
int dfs(int v){
B[v] = 1;
int run =0;
a[v]-=dp2[v];
b[v]-=dp2[v];
for(int u:g[v]){
if(B[u]){
if(dp1[u]<dp1[v]){
tr[u]++;
run++;
}
continue;
}
run+=dfs(u);
a[v]+=a[u];
b[v]+=b[u];
}
run-=tr[v];
run--;
tr[par[0][v]]--;
if(run>0||(a[v]==0&&b[v]==0)){
p[conv[{v,par[0][v]}]] = 'B';
// cout<<(run>0)<<" : : "<<v<<'\n';
}
else {
// cout<<v<< par[0][v]<<'\n';
if(a[v]>0){
if(e[conv[{v,par[0][v]}]].first==v)p[conv[{v,par[0][v]}]] = 'R';
else p[conv[{v,par[0][v]}]] = 'L';
}
else{
if(e[conv[{v,par[0][v]}]].first==v)p[conv[{v,par[0][v]}]] = 'L';
else p[conv[{v,par[0][v]}]] = 'R';
}
}
return run;
}
void dfs2(int v,int parv){
F[v] = 1;
dp1[v] = dp1[parv]+1;
par[0][v] = parv;
for(int u:g[v]){
if(!F[u]){
B[conv[{v,u}]] = 1;
dfs2(u,v);
}
}
}
long long lca(int v,int k){
if(k==0)return v;
return lca(par[(int)log2(k)][v],k-(1<<(int)log2(k)));
}
long long powmod(long long a, long long p, long long modd) {
long long ans = 1;
while (p > 0) {
if (p % 2 == 1) {
ans *= a;
ans %= modd;
p--;
}
if (p == 0)break;
a *= a;
a %= modd;
p /= 2;
}
return ans;
}
int main() {
ios::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
t = 1;
// cin >> t;
for (int hhh = 1;hhh <= t;hhh++) {
long long n, mx = 0, d = 0, m = 0, k = 0, k2 = 1, r = 0, rr = 0, l = 0, ll = 0, lll = 0, rrr = 0, inf = 1e18;
string s1;
char s3;
string s2;
string tt;
bool c = 1;
long double pi = 3.14159265359;
long double num =0;
long double num2;
// priority_queue<pair<long long, long long>> qq;
queue<int> qu;
// queue<pair<long long,pair<long long,long long>>> qm;
pair<int,int> aa;
// map<long long,long long> convbeg;
// set<long long> vv;
cin>>n>>m;
for(int i =0;i<m;i++){
cin>>l>>r;
e[i] = {l,r};
conv[{l,r}] = conv[{r,l}] = i;
g[l].push_back(r);
g[r].push_back(l);
}
for(int i =1;i<=n;i++){
if(!F[i])dfs2(i,0);
}
for(int i =0;i<m;i++){
if(!B[i])p[i] = 'B';
else B[i] = 0;
}
for(int j =1;j<=log2(n);j++){
for(int i =1;i<=n;i++){
par[j][i] = par[j-1][par[j-1][i]];
}
}
cin>>d;
for(int i =0;i<d;i++){
cin>>l>>r;
a[l]++;
b[r]++;
if(dp1[l]>dp1[r])swap(l,r);
r = lca(r,dp1[r]-dp1[l]);
// cout<<i<<" : "<<'\n';
for(int j = log2(n);j>-1;j--){
if(par[j][l]!=par[j][r]){
l = par[j][l];
r = par[j][r];
// cout<<l<<r<<'\n';
}
}
if(r!=l)r =par[0][r];
dp2[r]++;
// cout<<r<<l<<'\n';
}
for(int i =1;i<=n;i++)if(!B[i])dfs(i);
for(int i =0;i<m;i++)cout<<p[i];
}
}
