#include <bits/stdc++.h>
using namespace std;
typedef pair<int,int> pii;
const int MAXN = 100000;
int n, m, p;
vector<pii> adj[MAXN+1]; // (neighbor, edge_index)
int parent_edge[MAXN+1]; // edge index to parent in DFS tree
int depth[MAXN+1], low[MAXN+1], tin[MAXN+1], timer;
bool is_tree_edge[200000+5]; // mark edges in DFS tree
char ans[200000+5]; // answer for each edge: 'L','R','B'
int d1[MAXN+1], d2[MAXN+1]; // counters for non-tree edges and queries
pii edges[200000+5]; // original edges (u,v)
// 1) DFS to build tree, compute tin & low, mark tree edges
void dfs1(int u, int pe) {
tin[u] = low[u] = ++timer;
for (auto [v, ei] : adj[u]) {
if (ei == pe) continue;
if (!tin[v]) {
is_tree_edge[ei] = true;
parent_edge[v] = ei;
dfs1(v, ei);
low[u] = min(low[u], low[v]);
} else {
// back edge
low[u] = min(low[u], tin[v]);
}
}
}
// 2) Post-order DFS to assign edge directions
void dfs2(int u) {
for (auto [v, ei] : adj[u]) {
if (!is_tree_edge[ei] || edges[ei].first != u) continue;
// process child v
dfs2(v);
// default B
ans[ei] = 'B';
// if subtree sum for non-tree edges is zero, and no pending queries, skip
if (d1[v] != 0 || d2[v] != 0) {
// decide direction
// if queries more exit than enter, orient from v->u else u->v
bool go_up = (d2[v] > 0);
if (go_up) ans[ei] = 'R';
else ans[ei] = 'L';
}
// accumulate to parent
d1[u] += d1[v];
d2[u] += d2[v];
}
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
cin >> n >> m;
for (int i = 0; i < m; i++) {
int u, v;
cin >> u >> v;
edges[i] = {u, v};
adj[u].emplace_back(v, i);
adj[v].emplace_back(u, i);
}
// build DFS tree
dfs1(1, -1);
// non-tree edges: mark B and update d1
for (int i = 0; i < m; i++) {
if (!is_tree_edge[i]) {
ans[i] = 'B';
auto [u, v] = edges[i];
d1[u]++; d1[v]--;
}
}
// read queries, update d2
cin >> p;
while (p--) {
int a, b;
cin >> a >> b;
d2[a]++; d2[b]--;
}
// propagate and assign directions
dfs2(1);
// output
for (int i = 0; i < m; i++) cout << ans[i];
cout << '\n';
return 0;
}
