#include <bits/stdc++.h>
using namespace std;
#define pii pair<int, int>
#define s second
#define f first
vector<vector<pii>> graph;
vector<vector<pii>> cgraph;
vector<int> comp;
vector<int> low;
vector<int> num;
vector<bool> used;
vector<int> start;
vector<int> ende;
vector<int> dir;
vector<bool> vis;
stack<int> s;
int c = 0;
int d = 0;
void bicc(int i)
{
vis[i] = true;
low[i] = num[i] = c++;
s.push(i);
for (pii ele: graph[i])
{
if (used[ele.s]) continue;
used[ele.s] = true;
if (!vis[ele.f]) bicc(ele.f);
low[i] = min(low[i], low[ele.f]);
}
if (num[i]==low[i])
{
while (s.size() && num[s.top()]>=num[i])
{
comp[s.top()] = d;
s.pop();
}
d++;
}
}
int dfs(int i)
{
vis[i] = true;
int path = 0;
path -= ende[i];
path +=start[i];
for (pii ele:cgraph[i])
{
if (vis[ele.f]) continue;
dir[ele.s] = dfs(ele.f);
path += dir[ele.s];
if (dir[ele.s]<0) dir[ele.s] = ele.f;
else if (dir[ele.s]>0) dir[ele.s] = i;
else dir[ele.s] = -1;
}
return path;
}
int main()
{
int n, m;
cin >> n >> m;
graph = vector<vector<pii>>(n);
comp = vector<int>(n);
low = vector<int>(n);
num = vector<int>(n);
used = vector<bool>(m, false);
vis = vector<bool>(n, false);
vector<pii> edges(m);
for (int i = 0; i < m; i++)
{
int a, b;
cin >> a >> b;
a--; b--;
graph[a].push_back({b, i});
graph[b].push_back({a, i});
edges[i] = {a, b};
}
for (int i = 0; i < n; i++) if (!vis[i]) bicc(i);
cgraph = vector<vector<pii>>(d);
for (int i = 0; i < n; i++)
{
for (pii ele: graph[i])
{
if (comp[i]==comp[ele.f]) continue;
cgraph[comp[i]].push_back({comp[ele.f], ele.s});
}
}
start = vector<int>(d, 0);
ende = vector<int>(d, 0);
dir = vector<int>(m, -1);
vis = vector<bool>(d, false);
int t;
cin >> t;
while (t--)
{
int a, b;
cin >> a >> b;
a--; b--;
start[comp[a]]++;
ende[comp[b]]++;
}
for (int i = 0; i < d; i++)
{
if (vis[i]) continue;
dfs(i);
}
for (int i = 0; i < m; i++)
{
if (dir[i]==-1) cout << 'B';
else if (dir[i]==comp[edges[i].s]) cout << 'R';
else if (dir[i]==comp[edges[i].f]) cout << 'L';
}
return 0;
}
