#include <initializer_list>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <vector>
#include <algorithm>
#include <functional>
#include <fstream>
using namespace std;
#define int long long
signed main () {
ios::sync_with_stdio (false);
cin.tie (0);
cout.tie (0);
int N = 0, M = 0;
cin >> N >> M;
vector <vector <int> > gr (N + 1);
vector <pair <int, int> > in_v (M + 1);
map <pair <int, int>, vector <int> > revin;
map <pair <int, int>, int> backeg;
for (int i = 1; i <= M; i++) {
int a = 0, b = 0;
cin >> a >> b;
revin[{a, b}].emplace_back (i);
revin[{b, a}].emplace_back (i);
backeg[{a, b}]++;
backeg[{b, a}]++;
in_v[i] = {a, b};
gr[a].emplace_back (b);
gr[b].emplace_back (a);
}
// Step 1, depth
vector <int> depth (N + 1);
vector <vector <int> > depth_v (N + 1);
vector <bool> been (N + 1);
function <void(int, int)> dfs0 =
[&](int p, int dep) {
depth[p] = dep;
depth_v[dep].emplace_back (p);
been[p] = 1;
for (int& e : gr[p])
if (!been[e])
dfs0 (e, dep + 1);
};
for (int i = 1; i <= N; i++)
if (!been[i])
dfs0 (i, 0);
map <pair <int, int>, bool> m;
been = vector <bool> (N + 1);
vector <int> up (N + 1);
function <void(int, int)> dfs1 =
[&](int p, int par) {
been[p] = 1;
for (int& e : gr[p])
if (!been[e]) {
dfs1 (e, p);
up[p] += up[e];
} else if (depth[e] < depth[p] && (e != par || backeg[{e, p}] >= 2 || e == p)) {
up[e]--;
up[p]++;
}
if (up[p] == 0)
m[{par, p}] = m[{p, par}] = 1;
};
for (int i = 1; i <= N; i++)
if (!been[i])
dfs1 (i, 0);
been = vector <bool> (N + 1);
vector <vector <int> > binlift (
N + 1,
vector <int> (20)
);
vector <int> in (N + 1);
vector <int> out (N + 1);
out[0] = 2e9;
int timer = 1;
function <void(int,int)> dfs2 =
[&](int p, int par) {
in[p] = out[p] = ++timer;
been[p] = 1;
binlift[p][0] = par;
for (int i = 1; i < 20; i++)
binlift[p][i] = binlift[
binlift[p][i - 1]
][i - 1];
for (int& e : gr[p])
if (!been[e])
dfs2 (e, p);
out[p] = timer;
};
auto is_ancestor = [&in, &out](int a, int b) {
return in[a] <= in[b] && in[b] <= out[a];
};
for (int i = 1; i <= N; i++)
if (!been[i])
dfs2 (i, 0);
auto lca = [&](int a, int b) {
if (is_ancestor (a, b))
return a;
if (is_ancestor (b, a))
return b;
for (int p = 19; p >= 0; p--)
if (!is_ancestor (binlift[a][p], b))
a = binlift[a][p];
return binlift[a][0];
};
vector <int> up_pref (N + 1);
vector <int> down_pref (N + 1);
int Q = 0;
cin >> Q;
while (Q--) {
int a = 0, b = 0;
cin >> a >> b;
int c = lca (a, b);
// cout << "LCA " << a << ' ' << b << ' ' << c << '\n';
up_pref[a]++;
up_pref[c]--;
down_pref[b]++;
down_pref[c]--;
}
string ans (M, 'B');
// for (int i = 1; i <= N; i++)
// cout << i << ' ' << up_pref[i] << ' ' << down_pref[i] << '\n';
for (int i = N; i >= 1; i--)
for (int& e : depth_v[i]) {
if (binlift[e][0] != 0) {
if (up_pref[e] >= 1)
for (int& ind : revin[{e, binlift[e][0]}]) {
pair <int, int> p = in_v[ind];
if (p == (pair <int, int>){e, binlift[e][0]})
ans[ind - 1] = 'R';
else
ans[ind - 1] = 'L';
}
if (down_pref[e] >= 1)
for (int& ind : revin[{e, binlift[e][0]}]) {
pair <int, int> p = in_v[ind];
// cout << e << ' ' << binlift[e][0] << '\n';
// cout << ind << '\n';
if (p == (pair <int, int>){e, binlift[e][0]})
ans[ind - 1] = 'L';
else
ans[ind - 1] = 'R';
}
}
up_pref[binlift[e][0]] += up_pref[e];
down_pref[binlift[e][0]] += down_pref[e];
}
for (int i = 1; i <= M; i++)
if (!m[in_v[i]])
ans[i - 1] = 'B';
cout << ans << '\n';
}
// 12
