#include <bits/stdc++.h>
#define endl '\n'
using namespace std;
const int N=1e5+5, M=1e5+5;
int n, m, p, a[N], b[N], low[N], dep[N], c[N], d[N];
bool vis[N], bridge[M];
vector<int> g[N], t[N];
struct dsu {
int p[N], sz[N];
void init() {
for(int i=1; i<=n; i++)
p[i]=i, sz[i]=1;
}
int find(int u) {
if(u==p[u])
return u;
return p[u]=find(p[u]);
}
void unite(int u, int v) {
if((u=find(u))==(v=find(v)))
return;
if(sz[u]>sz[v])
swap(u, v);
sz[v]+=sz[u], p[u]=v;
}
} dsu;
void dfs(int u, int p) {
vis[u]=1;
dep[u]=dep[p]+1;
low[u]=dep[u];
bool f=0;
for(int e : g[u]) {
int v=u^a[e]^b[e];
if(v==p&&!f) {
f=1;
continue;
}
if(!vis[v]) {
dfs(v, u);
low[u]=min(low[u], low[v]);
if(low[v]>dep[u])
bridge[e]=1;
}
else
low[u]=min(low[u], dep[v]);
}
}
void dfs2(int u, int p) {
for(int e : t[u]) {
int v=u^a[e]^b[e];
if(v==p)
continue;
d[v]=d[u]+1;
dfs2(v, u);
c[u]+=c[v];
}
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
cin >> n >> m;
for(int i=1; i<=m; i++) {
cin >> a[i] >> b[i];
g[a[i]].push_back(i);
g[b[i]].push_back(i);
}
dsu.init();
for(int i=1; i<=n; i++)
if(!vis[i])
dfs(i, 0);
for(int i=1; i<=m; i++)
if(!bridge[i])
dsu.unite(a[i], b[i]);
for(int i=1; i<=m; i++) {
if(bridge[i]) {
a[i]=dsu.find(a[i]), b[i]=dsu.find(b[i]);
t[a[i]].push_back(i), t[b[i]].push_back(i);
}
}
cin >> p;
for(int i=1; i<=p; i++) {
int u, v;
cin >> u >> v;
c[dsu.find(u)]++, c[dsu.find(v)]--;
}
for(int i=1; i<=n; i++) {
if(dsu.p[i]==i&&!d[i]) {
d[i]=1;
dfs2(i, -1);
}
}
for(int i=1; i<=m; i++) {
if(!bridge[i]) {
cout << "B";
continue;
}
int u;
if(d[a[i]]>d[b[i]])
u=a[i];
else
u=b[i];
if(c[u]==0)
cout << "B";
else {
if((u==a[i]&&c[u]>0)||(u!=a[i]&&c[u]<0))
cout << "R";
else
cout << "L";
}
}
cout << endl;
return 0;
}
