#include <bits/stdc++.h>
#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#endif
#pragma GCC optimize("Ofast,unroll-loops")
using namespace std;
#define endl '\n'
#define ll long long
#define all(x) x.begin(), x.end()
vector<int> g[100005];
stack<int> s;
unordered_set<int> cgr[100005];
int Time = 0, scc = 0, id[100005], tim[100005], low[100005], val[100005], dist[100005];
bool ins[100005];
void tarjan(int n, int p) {
tim[n] = low[n] = ++Time;
s.push(n);
ins[n] = 1;
for (auto x : g[n]) {
if (x == p) {
p = -1;
continue;
}
if (tim[x] == 0) {
tarjan(x, n);
low[n] = min(low[n], low[x]);
}
else if (ins[x]) low[n] = min(low[n], tim[x]);
}
if (tim[n] == low[n]) {
while (s.top() != n) {
id[s.top()] = scc;
ins[s.top()] = 0;
s.pop();
}
id[s.top()] = scc;
ins[s.top()] = 0;
s.pop();
scc++;
}
}
void dfs(int n, int p) {
for (auto x : cgr[n]) {
if (x == p) continue;
dist[x] = dist[n] + 1;
dfs(x, n);
val[n] += val[x];
}
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int n, m;
cin >> n >> m;
int f[m], t[m];
for (int i = 0; i < m; i++) {
cin >> f[i] >> t[i];
g[f[i]].push_back(t[i]);
g[t[i]].push_back(f[i]);
}
for (int i = 1; i <= n; i++) if (!tim[i]) tarjan(i, -1);
for (int i = 0; i < m; i++) {
if (id[f[i]] != id[t[i]]) {
cgr[id[f[i]]].insert(id[t[i]]);
cgr[id[t[i]]].insert(id[f[i]]);
}
}
int p;
cin >> p;
for (int i = 0; i < p; i++) {
int a, b;
cin >> a >> b;
val[id[a]]++;
val[id[b]]--;
}
for (int i = 0; i < scc; i++) if (dist[i] == 0) dfs(i, -1);
for (int i = 0; i < m; i++) {
int a = id[f[i]], b = id[t[i]];
if (a == b) cout << "B";
if (dist[a] > dist[b]) {
if (val[a] > 0) cout << "R";
if (val[a] == 0) cout << "B";
if (val[a] < 0) cout << "L";
}
if (dist[a] < dist[b]) {
if (val[b] > 0) cout << "L";
if (val[b] == 0) cout << "B";
if (val[b] < 0) cout << "R";
}
}
}
