#include <bits/stdc++.h>
#define ll long long
using namespace std;
const int mxN = 1e5+5;
int n, m, dep[mxN], cnt[mxN], PU[mxN], PD[mxN], id[mxN], ans[mxN], it = 0, up[30][mxN];
vector <pair <int, int>> adj[mxN], adt[mxN];
void dfs(int u, int p, int ii) {
id[u] = ++it;
dep[u] = dep[p]+1;
up[0][u] = p;
for (auto [v, idx] : adj[u]) if (abs(idx) != abs(ii)) {
if (id[v]) {
if (id[v] > id[u]) cnt[u]--, ans[abs(idx)] = 3;
else if (id[v] < id[u]) cnt[u]++, ans[abs(idx)] = 3;
else if (id[v] == id[u]) ans[abs(idx)] = 3;
} else {
dfs(v, u, idx);
if (cnt[v] > 0) ans[abs(idx)] = 3;
cnt[u] += cnt[v];
adt[u].emplace_back(v, idx);
}
}
// cout << "DFS : " << u << ' ' << cnt[u] << '\n';
}
int LCA(int u, int v) {
if (dep[u] < dep[v]) swap(u, v);
int k = dep[u] - dep[v];
for (int i = 0; i < 30; i++) if (k & (1 << i)) u = up[i][u];
if (u == v) return u;
for (int i = 29; i >= 0; i--) if (up[i][u] != up[i][v]) u = up[i][u], v = up[i][v];
return up[0][u];
}
set <int> U[mxN], D[mxN];
void dfs2(int u, int p) {
for (auto [v, idx] : adt[u]) {
dfs2(v, u);
if (ans[abs(idx)] == 0 && U[v].size()) ans[abs(idx)] = (idx < 0 ? 1 : 2);
if (ans[abs(idx)] == 0 && D[v].size()) ans[abs(idx)] = (idx < 0 ? 2 : 1);
if (U[v].size() > U[u].size()) swap(U[u], U[v]);
for (auto &e : U[v]) U[u].emplace(e);
if (D[v].size() > D[u].size()) swap(D[u], D[v]);
for (auto &e : D[u]) D[u].emplace(e);
U[v].clear(), D[v].clear();
}
if (PU[u] != dep[u]) U[u].emplace(PU[u]);
if (PD[u] != dep[u]) D[u].emplace(PD[u]);
if (U[u].find(dep[u]) != U[u].end()) U[u].erase(U[u].find(dep[u]));
if (D[u].find(dep[u]) != D[u].end()) D[u].erase(D[u].find(dep[u]));
// cout << u << " : \n";
// for (auto &e : U[u]) cout << e << ' '; cout << '\n';
// for (auto &e : D[u]) cout << e << ' '; cout << '\n';
}
int main() {
ios::sync_with_stdio(0), cin.tie(0);
cin >> n >> m;
for (int i = 1, u, v; i <= m; i++) cin >> u >> v, adj[u].emplace_back(v, i), adj[v].emplace_back(u, -i);
dfs(1, 0, INT_MIN);
// for (int i = 1; i <= m; i++) cout << ans[i] << ' '; cout << '\n';
int q; cin >> q;
for (int i = 1; i <= n; i++) PU[i] = PD[i] = dep[i];
for (int c = 1; c < 30; c++) for (int i = 1; i <= n; i++) up[c][i] = up[c-1][up[c-1][i]];
while (q--) {
int u, v; cin >> u >> v;
int lca = LCA(u, v);
// cout << u << ' ' << v << ' ' << lca << '\n';
PU[u] = min(PU[u], dep[lca]);
PD[v] = min(PD[v], dep[lca]);
}
// for (int i = 1; i <= n; i++) cout << PU[i] << ' ' << PD[i] << '\n';
dfs2(1, 0);
for (int i = 1; i <= m; i++) {
if (ans[i] == 1) cout << 'L';
else if (ans[i] == 2) cout << 'R';
else cout << 'B';
}
cout << '\n';
}
