#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N = 1e5 + 5;
//INPUT
vector<pair<int, int> > g[N];
vector<pair<int, int> > conditions;
map<int, pair<int, int> > edge_index;
//BRIDGE FINDING
int disc[N], low[N];
set<int> bridges; //edge index
int tim = 0;
set<pair<int, int> > actually_multiple;
//DFS
bool vis[N]; //vis[edge index]
bool vis2[N];
//ANSWER
vector<int> answer(N, -2);
/*
= 0 --> B
= 1 --> R
= -1 --> L
*/
//BRIDGE TREE RELATED
int component_number[N]; //the component number of the node
vector<pair<int, int> > bridge_tree[N]; //connects component number only
int depth[N];
int DP[19][N];
//FOR UFDS
int ufds_parent[N];
int Find(int x)
{
if(x == ufds_parent[x])
{
return x;
}
return ufds_parent[x] = Find(ufds_parent[x]);
}
void Unite(int a, int b)
{
a = Find(a), b = Find(b);
ufds_parent[a] = b;
}
void dfs(int node, int par)
{
vis2[node] = true;
disc[node] = ++tim;
low[node] = tim;
//cout << "node = " << node << ", time = " << tim << "\n";
for(auto i: g[node])
{
int to = i.first, edge_idx = i.second;
if(to == par)
{
continue;
}
if(vis2[to])
{
low[node] = min(low[node], disc[to]);
continue;
}
vis[edge_idx] = true;
dfs(to, node);
low[node] = min(low[node], low[to]);
if(disc[node] < low[to] && !actually_multiple.count({min(node, to), max(node, to)}))
{
bridges.insert(edge_idx);
}
/*if(node == 5 && to == 6)
{
cout << disc[node] << " " << low[to] << "\n";
}*/
}
}
//in dfs2 --> vis[node]
void dfs2(int node, int par, int component)
{
vis[node] = true;
component_number[node] = component;
for(auto i: g[node])
{
int to = i.first, edge_idx = i.second;
if(!vis[to] && !bridges.count(edge_idx))
{
dfs2(to, node, component);
}
}
}
void dfs_component(int node, int par)
{
vis2[node] = true;
for(auto i: bridge_tree[node])
{
int to = i.first, edge_idx = i.second;
if(to != par)
{
depth[to] = depth[node] + 1;
DP[0][to] = node;
dfs_component(to, node);
}
}
}
int LCA(int x, int y)
{
/*int f = 0;
if(x == 2 && y == 6)
{
cout << "LCA: " << depth[x] << " " << depth[y] << "\n";
f = 1;
}*/
if(depth[x] > depth[y])
{
swap(x, y);
}
int diff = depth[y] - depth[x];
for(int i = 18; i >= 0; i--)
{
if(diff >= (1 << i))
{
diff -= (1 << i);
y = DP[i][y];
}
}
/*if(f == 1)
{
cout << "now: " << x << ", " << y << "\n";
}*/
if(x == y)
{
return x;
}
for(int i = 18; i >= 0; i--)
{
if(DP[i][x] != DP[i][y])
{
x = DP[i][x];
y = DP[i][y];
}
}
return DP[0][x];
}
void Solve()
{
int n, m;
cin >> n >> m;
for(int i = 1; i <= n; i++)
{
ufds_parent[i] = i;
}
set<pair<int, int> > multiple_occurrences;
set<int> to_be_considered;
for(int i = 1; i <= m; i++)
{
int u, v, f = 0;
cin >> u >> v;
if(u < v)
{
f = 1;
swap(u, v);
}
if(!multiple_occurrences.count({v, u}) && v != u) //removing all multiple and self edges
{
multiple_occurrences.insert({v, u});
g[u].push_back(make_pair(v, i));
g[v].push_back(make_pair(u, i));
to_be_considered.insert(i);
}
else
{
answer[i] = 0;
if(v != u)
{
actually_multiple.insert({v, u});
}
}
if(f == 1)
{
swap(u, v);
}
edge_index[i] = {u, v};
}
/*for(auto i: actually_multiple)
{
cout << i.first << " " << i.second << "\n";
}
cout << "actually_multiple over" << endl;*/
for(int i = 1; i <= n; i++)
{
if(!vis2[i])
{
dfs(i, -1);
}
}
/*for(auto i: bridges)
{
cout << edge_index[i].first << " " << edge_index[i].second << "\n";
}
cout << "bridges over" << endl;*/
for(int i = 0; i < N; i++)
{
vis[i] = false;
}
int component = 1;
for(int i = 1; i <= n; i++)
{
if(!vis[i])
{
dfs2(i, -1, component++);
}
}
for(int i = 1; i <= m; i++)
{
if(edge_index[i].first == edge_index[i].second || !to_be_considered.count(i))
{
continue;
}
if(component_number[edge_index[i].first] != component_number[edge_index[i].second])
{
bridge_tree[component_number[edge_index[i].first]].push_back(make_pair(component_number[edge_index[i].second], i));
bridge_tree[component_number[edge_index[i].second]].push_back(make_pair(component_number[edge_index[i].first], i));
}
else
{
answer[i] = 0;
}
}
int p;
cin >> p;
for(int i = 1; i <= p; i++)
{
int start, dest;
cin >> start >> dest;
start = component_number[start];
dest = component_number[dest];
if(start != dest)
{
//cout << "conditions: " << start << ", " << dest << "\n";
conditions.push_back(make_pair(start, dest));
}
}
/*for(int i = 0; i < conditions.size(); i++)
{
cout << conditions[i].first << " " << conditions[i].second << "\n";
}
for(int i = 1; i <= n; i++)
{
cout << component_number[i] << " ";
}
cout << endl;
cout << component << "\n";
cout << "bridge tree output\n";
for(int i = 1; i < component; i++)
{
for(int j = 0; j < bridge_tree[i].size(); j++)
{
cout << i << " " << bridge_tree[i][j].first << "\n";
}
}*/
//cout << "bye" << endl;
for(int i = 1; i <= n; i++)
{
vis2[i] = false;
}
for(int i = 1; i < component; i++)
{
if(!vis2[i])
{
depth[i] = 0;
DP[0][i] = -1;
dfs_component(i, -1);
}
}
//cout << "hi" << endl;
for(int i = 1; i < 18; i++)
{
for(int j = 1; j < component; j++)
{
if(DP[i - 1][j] == -1)
{
DP[i][j] = -1;
}
else
{
DP[i][j] = DP[i - 1][DP[i - 1][j]];
}
}
}
/*for(int i = 0; i < 18; i++)
{
for(int j = 1; j < component; j++)
{
cout << DP[i][j] << " ";
}
cout << "\n";
}*/
set<pair<int, int> > should_be_satisfied;
//cout << "doing conditions" << endl;
for(int i = 0; i < conditions.size(); i++)
{
int lca = LCA(conditions[i].first, conditions[i].second);
int node = conditions[i].first;
//cout << "conditions[i].first = " << conditions[i].first << ", conditions[i].second = " << conditions[i].second << ", lca = " << lca << "\n";
node = Find(node);
while(depth[node] > depth[lca])
{
should_be_satisfied.insert(make_pair(node, DP[0][node]));
Unite(node, DP[0][node]);
//cout << node << " -> " << DP[0][node] << "\n";
node = Find(node);
}
node = Find(conditions[i].second);
while(depth[node] > depth[lca])
{
should_be_satisfied.insert(make_pair(DP[0][node], node));
//cout << node << " <- " << DP[0][node] << "\n";
Unite(node, DP[0][node]);
node = Find(node);
}
}
//cout << "reached here" << endl;
for(int i = 1; i <= m; i++)
{
int x = component_number[edge_index[i].first], y = component_number[edge_index[i].second];
//cout << "x = " << x << ", y = " << y << "\n";
answer[i] = 0;
if(x != y)
{
if(should_be_satisfied.count({x, y}))
{
answer[i] = 1;
}
else if(should_be_satisfied.count({y, x}))
{
answer[i] = -1;
}
}
if(actually_multiple.count({min(edge_index[i].first, edge_index[i].second), max(edge_index[i].first, edge_index[i].second)}))
{
answer[i] = 0;
}
if(answer[i] == -1)
{
cout << "L";
}
else if(answer[i] == 1)
{
cout << "R";
}
else {
cout << "B";
}
}
cout << "\n";
}
int32_t main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
Solve();
return 0;
}
