#include <bits/stdc++.h> using namespace std; class Solver{ private: //Graph int node_num, edge_num, query_num; vector<vector<tuple<int, int, bool>>> graph; //DFS Tree vector<vector<int>> dfs_tree; vector<int> root, depth, edge_id, dp, vals; vector<bool> edge_dir, vis_node, vis_edge; void build_dfs_tree(int curr){ for (auto [child, edge, dir] : graph[curr]){ if (!vis_node[child]){ depth[child] = depth[curr] + 1; vis_node[child] = true; vis_edge[edge] = true; dfs_tree[curr].push_back(child); edge_id[child] = edge; edge_dir[child] = dir; build_dfs_tree(child); } else if (!vis_edge[edge]){ vis_edge[edge] = true; int u = curr, v = child; if (depth[u] > depth[v]) swap(u, v); dp[u]--; dp[v]++; } } } void calc_dp(int curr){ for (int child : dfs_tree[curr]) calc_dp(child); for (int child : dfs_tree[curr]) dp[curr] += dp[child]; } void update_path(int u, int v){ vals[u]++; vals[v]--; } void sum_up_vals(int curr){ for (int child : dfs_tree[curr]) sum_up_vals(child); for (int child : dfs_tree[curr]) vals[curr] += vals[child]; } public: Solver() { cin >> node_num >> edge_num; graph.resize(node_num); for (int i = 0; i < edge_num; i++){ int u, v; cin >> u >> v; u--, v--; graph[u].push_back({v, i, true}); graph[v].push_back({u, i, false}); } dfs_tree.resize(node_num); depth.resize(node_num, 0); edge_id.resize(node_num, 0); dp.resize(node_num, 0); vals.resize(node_num, 0); edge_dir.resize(node_num); vis_node.resize(node_num, false); vis_edge.resize(edge_num, false); for (int i = 0; i < node_num; i++){ if (!vis_node[i]){ root.push_back(i); vis_node[i] = true; build_dfs_tree(i); } } for (int rt : root) calc_dp(rt); cin >> query_num; while (query_num--){ int u, v; cin >> u >> v; u--, v--; update_path(u, v); } for (int rt : root) sum_up_vals(rt); vector<char> ans(edge_num, 'B'); for (int i = 0; i < node_num; i++){ if (dp[i] == 0){ char dir = 'B'; if (vals[i] > 0) dir = edge_dir[i] ? 'L' : 'R'; if (vals[i] < 0) dir = edge_dir[i] ? 'R' : 'L'; ans[edge_id[i]] = dir; } } for (char dir : ans) cout << dir; } }; int main(){ ios::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr); Solver(); return 0; }