#include <bits/stdc++.h>
#define s second
#define f first
#define pb push_back
#define left (h<<1),l,((l+r)>>1)
#define right ((h<<1)|1),((l+r)>>1) + 1,r
using namespace std;
const int N = 100005;
int tin[N],low[N],a[N],b[N],ID[N],d[25][N];
int O[N],C[N];
bool bridge[N],vis[N];
vector <int> adj[N],vec[N];
vector <pair<int,int> > v[N];
int idx,cnt,n;
void dfs(int x,int par){
vis[x] = 1;
tin[x] = low[x] = cnt++;
for (auto [to,id]: v[x]){
if (to == par) continue;
if (vis[to]){
low[x] = min(low[x], tin[to]);
}else{
dfs(to,x);
low[x] = min(low[x], low[to]);
if (low[to] > tin[x]) bridge[id] = 1;
}
}
}
void dfs1(int x){
ID[x] = idx;
vis[x] = 1;
for (auto [to,id]: v[x]){
if (!vis[to] && !bridge[id]) dfs1(to);
else if (!vis[to] && bridge[id]) vec[idx].pb(to);
}
}
void dfs2(int x,int par){
vis[x] = 1;
d[0][x] = par;
tin[x] = tin[par] + 1;
for (int to: adj[x])
if (!vis[to]) dfs2(to,x);
}
void dfs3(int x,int par){
vis[x]=1;
for (int to: adj[x])
if (to!=par) {
dfs3(to,x);
O[x] += O[to];
C[x] += C[to];
}
}
int lca(int x,int y){
if (tin[x] < tin[y]) swap(x,y);
for (int j = 18; j >= 0; j--)
if (tin[d[j][x]] >= tin[y]) x = d[j][x];
if (x == y) return x;
for (int j = 18; j >=0; j--)
if(d[j][x] != d[j][y]) x = d[j][x],y = d[j][y];
return d[0][x];
}
int main (){
ios_base::sync_with_stdio(0),cin.tie(NULL),cout.tie(NULL);
int m;
cin>>n>>m;
for (int i = 1; i <= m; i++){
cin>>a[i]>>b[i];
v[a[i]].pb({b[i],i});
v[b[i]].pb({a[i],i});
}
for (int i= 1; i <= n; i++)
if (!vis[i]) dfs(i,i);
for (int i = 1; i <= n; i++) {
sort(v[i].begin(),v[i].end());
for (int j = 1; j < v[i].size(); j++)
if (v[i][j].f == v[i][j - 1].f) bridge[v[i][j].s] = bridge[v[i][j - 1].s] = 0;
}
for (int i= 1; i <= n; i++)
vis[i] = 0;
idx = 0;
for (int i = 1; i <= n; i++)
if (!vis[i]) idx++,dfs1(i);
for (int i = 1; i <= n; i++)
for (int x: vec[i])
adj[i].pb(ID[x]),adj[ID[x]].pb(i);
for (int i = 1; i <= n; i++)
tin[i] = 0,vis[i] = 0;
cnt=0;
for (int i = 1; i <= n; i++)
if (!vis[i]) dfs2(i,i);
for (int j = 1; j < 19; j++)
for (int i = 1; i <= n; i++)
d[j][i] = d[j - 1][d[j - 1][i]];
int k;
cin>>k;
for (int i = 1; i <= k; i++){
int x,y;
cin>>x>>y;
x = ID[x],y = ID[y];
int c = lca(x,y);
O[x]++; O[c]--;
C[y]++; C[c]--;
}
for (int i = 1; i <= n; i++) vis[i] = 0;
for (int i = 1; i <= n; i++) if (!vis[i]) dfs3(i,i);
for (int i = 1; i <= m; i++){
if (!bridge[i]) cout<<'B';
else{
int x = ID[a[i]],y = ID[b[i]];
if (tin[x] >= tin[y]){
if(O[x] && !C[x]) cout<<'R';
else if (!O[x] && C[x]) cout<<'L';
else cout<<'B';
}else{
if(O[y] && !C[y]) cout<<'L';
else if (!O[y] && C[y]) cout<<'R';
else cout<<'B';
}
}
}
}
