#include <bits/stdc++.h>
using namespace std;
#define pii pair <int, int>
#define fi first
#define se second
#define mp make_pair
const int NM = 1e5, LOG = 16;
int n, m, a[NM+5], b[NM+5];
vector <pii> adj[NM+5];
int p, u[NM+5], v[NM+5];
map <pii, int> cnt;
int timer = 0, num[NM+5], low[NM+5];
bool is_bridge[NM+5];
int parent[NM+5], sz[NM+5];
vector <int> g[NM+5];
int dep[NM+5], jump[NM+5][LOG+5], dp[NM+5][LOG+5];
void dfs(int u, int p){
low[u] = num[u] = ++timer;
for (pii _ : adj[u]){
int v = _.fi, id = _.se;
if (v == p) continue;
if (num[v] > 0){
low[u] = min(low[u], num[v]);
}
else{
dfs(v, u);
low[u] = min(low[u], low[v]);
if (cnt[mp(u, v)] == 1 && low[v] > num[u]) is_bridge[id] = 1;
}
}
}
void make_set(int v){
parent[v] = v;
sz[v] = 1;
}
int find_set(int v){
return parent[v] == v ? v : parent[v] = find_set(parent[v]);
}
void union_sets(int u, int v){
u = find_set(u);
v = find_set(v);
if (u == v) return;
if (sz[u] < sz[v]) swap(u, v);
parent[v] = u;
sz[u] += sz[v];
}
void dfs2(int u, int p){
dep[u] = (p == -1 ? 0 : dep[p]+1);
jump[u][0] = p;
for (int i = 1; i <= LOG; i++)
if (jump[u][i-1] == -1) jump[u][i] = -1;
else jump[u][i] = jump[jump[u][i-1]][i-1];
for (int v : g[u]){
if (v == p) continue;
dfs2(v, u);
}
}
int lca(int u, int v){
if (dep[u] < dep[v]) swap(u, v);
for (int i = LOG; i >= 0; i--)
if (dep[u]-(1<<i) >= dep[v]) u = jump[u][i];
if (u == v) return u;
for (int i = LOG; i >= 0; i--)
if (jump[u][i] != jump[v][i]){
u = jump[u][i];
v = jump[v][i];
}
return jump[u][0];
}
void update(int u, int p, int val){
for (int i = LOG; i >= 0; i--)
if (dep[u]-(1<<i) >= dep[p]){
dp[u][i] = val;
u = jump[u][i];
}
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> n >> m;
for (int i = 1; i <= m; i++){
cin >> a[i] >> b[i];
cnt[mp(a[i], b[i])]++;
cnt[mp(b[i], a[i])]++;
if (cnt[mp(a[i], b[i])] > 1) continue;
adj[a[i]].push_back(mp(b[i], i));
adj[b[i]].push_back(mp(a[i], i));
}
cin >> p;
for (int i = 1; i <= p; i++)
cin >> u[i] >> v[i];
for (int i = 1; i <= n; i++){
if (!num[i]) dfs(i, -1);
make_set(i);
}
for (int i = 1; i <= m; i++){
if (!is_bridge[i]) union_sets(a[i], b[i]);
}
for (int i = 1; i <= m; i++){
int u = find_set(a[i]), v = find_set(b[i]);
if (u != v){
g[u].push_back(v);
g[v].push_back(u);
}
}
for (int u = 1; u <= n; u++){
if (parent[u] != u) continue;
if (jump[u][0] == 0) dfs2(u, -1);
}
for (int i = 1; i <= p; i++){
int x = find_set(u[i]), y = find_set(v[i]);
if (x == y) continue;
int p = lca(x, y);
update(x, p, 1);
update(y, p, 2);
}
for (int i = LOG; i > 0; i--){
for (int u = 1; u <= n; u++){
if (parent[u] != u || dp[u][i] == 0) continue;
dp[u][i-1] = dp[u][i];
dp[jump[u][i-1]][i-1] = dp[u][i];
}
}
for (int i = 1; i <= m; i++){
int u = find_set(a[i]), v = find_set(b[i]);
if (u == v){
cout << 'B';
continue;
}
if (dep[u] > dep[v]){
if (dp[u][0] == 0) cout << 'B';
else if (dp[u][0] == 1) cout << 'R';
else cout << 'L';
}
else{
if (dp[v][0] == 0) cout << 'B';
else if (dp[v][0] == 1) cout << 'L';
else cout << 'R';
}
}
return 0;
}
