#include <bits/stdc++.h>
using namespace std;
const int LOG = 20;
struct DSU {
DSU() {}
void build(int N) {
P.resize(N + 1, 0);
}
vector<int> P;
int find(int a) {
if (P[a] == 0) return a;
return P[a] = find(P[a]);
}
void unite(int a, int b) {
a = find(a), b = find(b);
if (a == b) return;
P[b] = a;
}
};
struct Graph_with_Tarjan {
Graph_with_Tarjan(int N, int M) {
mrk.resize(M + 1, 0);
vis.resize(N + 1, 0);
bck.resize(M + 1, 0);
adj.resize(N + 1);
tin.resize(N + 1);
low.resize(N + 1);
}
vector<vector<pair<int, int>>> adj;
vector<int> mrk, tin, low, vis, bck;
void add_edge(int u, int v, int i) {
adj[u].push_back({v, i});
adj[v].push_back({u, i});
}
void dfs(int u, int ip, int& t) {
tin[u] = low[u] = t++, vis[u] = 1;
for (auto &[v, i]: adj[u]) {
if (i == ip) continue;
if (!vis[v]) {
dfs(v, i, t);
low[u] = min(low[u], low[v]);
if (low[v] > tin[u]) {
mrk[i] = 1;
}
} else {
low[u] = min(low[u], tin[v]);
bck[i] = 1;
}
}
}
};
struct Tree_with_LCA {
Tree_with_LCA(int N, int M) {
up.resize(N + 1, vector<int>(LOG, 0));
mrk.resize(M + 1, 0);
adj.resize(N + 1);
dep.resize(N + 1);
id.resize(N + 1);
dsu.build(N);
}
vector<vector<pair<int, int>>> adj;
vector<vector<int>> up;
vector<int> dep, mrk, id;
DSU dsu;
void add_edge(int u, int v, int i) {
adj[u].push_back({v, i});
adj[v].push_back({u, i});
}
void dfs(int u, int p, int d) {
dep[u] = d, up[u][0] = p;
for (auto &[v, i]: adj[u]) {
if (v == p) continue;
id[v] = i;
dfs(v, u, d + 1);
}
}
void build(int n) {
for (int i = 1; i < LOG; i++) {
for (int u = 1; u <= n; u++) {
up[u][i] = up[up[u][i - 1]][i - 1];
}
}
}
int lift(int u, int x) {
for (int i = LOG - 1; i >= 0; i--) {
if (x & (1 << i)) {
u = up[u][i];
}
}
return u;
}
int LCA(int u, int v) {
if (dep[u] < dep[v]) swap(u, v);
u = lift(u, dep[u] - dep[v]);
for (int i = LOG - 1; i >= 0; i--) {
if (up[u][i] != up[v][i]) {
u = up[u][i], v = up[v][i];
}
}
return up[u][0];
}
void update(int u, int v, int x) {
while (dep[u = dsu.find(u)] > dep[v]) {
mrk[id[u]] = x;
dsu.unite(v, u);
u = up[u][0];
}
}
};
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n, m;
cin >> n >> m;
vector<pair<int, int>> edge(m);
for (auto &[u, v]: edge) {
cin >> u >> v;
}
Graph_with_Tarjan graph(n, m);
for (int i = 0; i < m; i++) {
auto [u, v] = edge[i];
graph.add_edge(u, v, i);
}
int timer = 0;
graph.dfs(1, 0, timer);
Tree_with_LCA tree(n, m);
for (int i = 0; i < m; i++) {
if (!graph.bck[i]) {
auto [u, v] = edge[i];
tree.add_edge(u, v, i);
}
}
tree.dfs(1, 0, 0);
tree.build(n);
int q;
cin >> q;
while (q--) {
int u, v;
cin >> u >> v;
int lca = tree.LCA(u, v);
tree.update(u, lca, 1);
tree.update(v, lca, 2);
}
for (int i = 0; i < m; i++) {
if (graph.mrk[i]) {
auto [u, v] = edge[i];
if (tree.mrk[i] == 0) {
cout << 'B';
} else if (tree.mrk[i] == 1) {
if (v == tree.up[u][0]) {
cout << 'R';
} else {
cout << 'L';
}
} else {
if (v == tree.up[u][0]) {
cout << 'L';
} else {
cout << 'R';
}
}
} else {
cout << 'B';
}
}
cout << '\n';
return 0;
}
