#include<bits/stdc++.h>
#define int long long
using namespace std;
vector<vector<pair<int,int> > >n1;
vector<int> visited;
vector<int> torder;
vector<int> cc;
vector<int> link1;
vector<int> preorder;
vector<int> up;
vector<int> down;
vector<vector<pair<int,int> > > n3;
int c = 0;
int c1 = 0;
string s ="";
vector<pair<int,int> > edges;
vector<int> pa1;
void dfs1(int x, int p){
visited[x] = 1;
preorder[x] = c;
c++;
link1[x] = c-1;
for (int i = 0;i<n3[x].size();i++){
if (n3[x][i].second==p) continue;
else if (visited[n3[x][i].first]==-1) {
dfs1(n3[x][i].first,n3[x][i].second);
link1[x] = min(link1[x],link1[n3[x][i].first]);
}
else link1[x] = min(link1[x],preorder[n3[x][i].first]);
}
}
void dfs(int x, int p){
visited[x] = 1;
cc[x] = c1;
for (int i = 0;i<n3[x].size();i++){
if (n3[x][i].second==p) continue;
if (link1[n3[x][i].first]<=preorder[x] and visited[n3[x][i].first]==-1)dfs(n3[x][i].first,n3[x][i].second);
}
}
vector<vector<int> > pa;
vector<int> dist;
vector<int> depth;
int hi1(int x, int p){
for (int i = 19;i>=0;i--){
if ((1<<i)<=p){
x = pa[x][i];
p = p-(1<<i);
}
}
return x;
}
int lca(int x, int y){
if (depth[x]>depth[y]) swap(x,y);
for (int i = 19;i>=0;i--){
if (pa[y][i]!=-1 and depth[pa[y][i]]>=depth[x]) y = pa[y][i];
}
if (x==y) return x;
for (int i = 19;i>=0;i--){
if (pa[x][i]!=pa[y][i]) {
x = pa[x][i];
y = pa[y][i];
}
}
return pa[x][0];
}
void dfs2(int x, int p){
visited[x] = 1;
for (int i = 0;i<n1[x].size();i++){
if (n1[x][i].first!=p and visited[n1[x][i].first]==-1){
depth[n1[x][i].first] = depth[x]+1;
pa[n1[x][i].first][0] = x;
pa1[n1[x][i].first] = n1[x][i].second;
dfs2(n1[x][i].first,x);
}
}
}
void dfs3(int x, int p){
for (int i = 0;i<n1[x].size();i++){
if (n1[x][i].first==p) continue;
int y = n1[x][i].first;
int id = n1[x][i].second;
dfs3(n1[x][i].first,x);
up[x] += up[n1[x][i].first];
down[x] += down[n1[x][i].first];
if (up[y] && down[y]) s[id] = 'B';
else if (up[y]) {
if (cc[edges[id].first] == y) s[id] = 'R';
else s[id] = 'L';
}
else if (down[y]) {
if (cc[edges[id].first] == y) s[id] = 'L';
else s[id] = 'R';
}
}
}
signed main(){
int n,m,p;
cin>>n>>m;
link1.assign(n,1e9);
preorder.resize(n);
n3.resize(n);
visited.assign(n,-1);
cc.assign(n,-1);
for (int i = 0;i<m;i++){
int a,b;
cin>>a>>b;
n3[a-1].push_back(make_pair(b-1,i));
n3[b-1].push_back(make_pair(a-1,i));
edges.push_back(make_pair(a-1,b-1));
}
for (int i = 0;i<n;i++){
if (visited[i]==-1) dfs1(i,-1);
}
visited.clear();
visited.assign(n,-1);
for (int i = 0;i<n;i++){
if (visited[i]==-1){
dfs(i,-1);
c1++;
}
}
n1.resize(c1);
depth.resize(c1);
pa.resize(c1);
pa1.resize(c1);
for (int i = 0;i<n;i++){
for (int j = 0;j<n3[i].size();j++){
if (link1[n3[i][j].first]>preorder[i]){
n1[cc[i]].push_back(make_pair(cc[n3[i][j].first],n3[i][j].second));
n1[cc[n3[i][j].first]].push_back(make_pair(cc[i],n3[i][j].second));
}
}
}
for (int i = 0;i<c1;i++) pa[i].assign(20,-1);
visited.clear();
visited.assign(c1,-1);
for (int i = 0;i<n;i++){
if (visited[cc[i]]==-1) dfs2(cc[i],-1);
}
for (int i = 1;i<20;i++){
for (int j = 0;j<c1;j++){
if (pa[j][i-1]!=-1) pa[j][i] = pa[pa[j][i-1]][i-1];
else pa[j][i] = -1;
}
}
for (int i = 0;i<m;i++) s = s+'B';
cin>>p;
up.assign(c1,0);
down.assign(c1,0);
for (int i = 0;i<p;i++){
int a,b;
cin>>a>>b;
a = cc[a-1];
b = cc[b-1];
int c = lca(a,b);
up[a]++;
up[c]--;
down[b]++;
down[c]--;
}
for (int i = 0;i<c1;i++){
if (pa[i][0]==-1){
dfs3(i,-1);
}
}
cout<<s;
return 0;
}
