#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define sp ' '
#define en '\n'
#define smin(a, b) a = min(a, b)
#define smax(a, b) a = max(a, b)
using namespace std;
const int N = 1e5 + 2;
const ll linf = 1e18;
vector<array<int, 3>> g[N];
int a[N], dep[N], mn[N], ans[N], tsz;
void Dfs(int s, int e) {
dep[s] = mn[s] = ++tsz;
for (auto u : g[s]) {
if (u[1] == e) continue;
if (dep[u[0]] == 0) {
Dfs(u[0], u[1]);
a[s] += a[u[0]];
smin(mn[s], mn[u[0]]);
if (mn[u[0]] > dep[s]) {
if (a[u[0]] > 0) ans[u[1]] = u[2] ^ 1;
else if (a[u[0]] < 0) ans[u[1]] = u[2];
}
}
else smin(mn[s], dep[u[0]]);
}
}
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int n, m;
cin >> n >> m;
for (int i = 0; i < m; i++) {
int u, v;
cin >> u >> v;
g[u].push_back({v, i, 0});
g[v].push_back({u, i, 1});
}
for (int i = 0; i < m; i++) ans[i] = 2;
int p; cin >> p;
for (int i = 0; i < p; i++) {
int u, v;
cin >> u >> v;
a[u] += 1;
a[v] -= 1;
}
Dfs(1, -1);
for (int i = 0; i < m; i++) {
if (ans[i] == 0) cout << 'R';
if (ans[i] == 1) cout << 'L';
if (ans[i] == 2) cout << 'B';
}
cout << en;
return 0;
}
