#include <iostream>
#include <vector>
#include <algorithm>
#include <cassert>
#define pb push_back
#define all(xs) xs.begin(), xs.end()
#define rep(i, n) for (int i=0; i<(n); i++)
using namespace std;
typedef pair<int, int> P;
#define _1 first
#define _2 second
struct UnionFind {
int N;
vector<int> U, R;
UnionFind(int N) : N(N), U(N), R(N) {
rep(i, N) U[i] = i, R[i] = 1;
}
int find(int x) {
if (U[x] == x) return x;
return U[x] = find(U[x]);
}
void unite(int x, int y) {
x = find(x), y = find(y);
if (x == y) return;
if (R[x] < R[y]) swap(x, y);
U[y] = x;
R[x] += R[y];
}
};
int N, M, K;
vector<P> G[100000];
P E[100000];
bool bridge[100000];
bool up[100000], down[100000];
int R[100000], T[100000];
bool used[100000];
void dfs(int x, int p, int r) {
used[x] = true;
R[x] = r;
for (P pp : G[x]) {
int t = pp._1, pi = pp._2;
if (pi == p) continue;
if (used[t]) {
if (R[t] < R[x]) T[t]++, T[x]--;
continue;
}
dfs(t, pi, r+1);
}
}
void dfs2(int x, int p) {
used[x] = true;
for (P pp : G[x]) {
int t = pp._1, pi = pp._2;
if (pi == p || used[t]) continue;
dfs2(t, pi);
T[x] += T[t];
}
if (p != -1 && T[x] == 0) bridge[p] = true;
}
int U[20][100000];
int W[2][100000];
void dfs3(int x, int p, int r) {
used[x] = true;
U[0][x] = p;
R[x] = r;
for (P pp : G[x]) {
int t = pp._1;
if (t == p) continue;
dfs3(t, x, r+1);
}
}
int lca(int x, int y) {
if (R[x] < R[y]) swap(x, y);
for (int k=19; k>=0; k--) if (((R[x]-R[y])>>k)&1) x = U[k][x];
if (x == y) return x;
for (int k=19; k>=0; k--) if (U[k][x] != U[k][y]) x = U[k][x], y = U[k][y];
return U[0][x];
}
void dfs4(int x, int p, int pe) {
for (P pp : G[x]) {
int t = pp._1;
if (t == p) continue;
dfs4(t, x, pp._2);
W[0][x] += W[0][t];
W[1][x] += W[1][t];
}
if (p != -1) {
assert(!W[0][x] || !W[1][x]);
if (W[0][x]) up[pe] = true;
else if (W[1][x]) down[pe] = true;
else up[pe] = down[pe] = true;
}
}
signed main() {
cin >> N >> M;
rep(i, M) {
int a, b;
cin >> a >> b;
a--, b--;
E[i] = P(a, b);
if (a == b) {
up[i] = down[i] = true;
continue;
}
G[a].pb(P(b, i));
G[b].pb(P(a, i));
}
rep(i, N) used[i] = false;
rep(i, N) if (!used[i]) dfs(i, -1, 0);
rep(i, N) used[i] = false;
rep(i, N) if (!used[i]) dfs2(i, -1);
// build a tree
rep(i, N) G[i].clear();
//rep(i, M) if(bridge[i])cout<<"i="<<i<<": "<<E[i]._1<<","<<E[i]._2<<" is a bridge\n";
UnionFind uf(N);
rep(i, M) if (!bridge[i]) {
up[i] = down[i] = true;
uf.unite(E[i]._1, E[i]._2);
}
rep(i, M) if (bridge[i]) {
int u = uf.find(E[i]._1), v = uf.find(E[i]._2);
G[u].pb(P(v, i));
G[v].pb(P(u, i));
}
vector<int> roots;
rep(i, N) used[i] = false;
rep(i, N) if (uf.find(i) == i && !used[i]) dfs3(i, -1, 0), roots.pb(i);
rep(k, 19) {
rep(i, N) {
if (uf.find(i) != i) continue;
if (U[k][i] == -1) U[k+1][i] = -1;
U[k+1][i] = U[k][U[k][i]];
}
}
cin >> K;
rep(i, K) {
int x, y;
cin >> x >> y;
x--, y--;
x = uf.find(x), y = uf.find(y);
if (x == y) continue;
int g = lca(x, y);
W[0][x]++, W[0][g]--; // x->g
W[1][y]++, W[1][g]--; // y->g
}
for (int x : roots) dfs4(x, -1, -1);
rep(i, M) if (bridge[i]) {
int u = uf.find(E[i]._1), v = uf.find(E[i]._2);
if (R[v] < R[u]) swap(up[i], down[i]);
}
rep(i, M) {
assert(up[i] || down[i]);
if (up[i] && down[i]) cout << 'B';
else if (up[i]) cout << 'L';
else if (down[i]) cout << 'R';
}
cout << '\n';
return 0;
}
