#include <bits/stdc++.h>
using namespace std;
#define eb emplace_back
#define fi first
#define se second
struct edge {
int u, v;
};
using ii = pair <int, int>;
const int N = 1e5 + 5;
const int LG = 18;
int col[N], bri[N], pred[N];
int num[N], low[N], tim;
int par[N], p[LG][N], d[N];
vector <ii> adj[N]; edge ed[N];
int find_set(int u) {
return u == par[u] ?
u : par[u] = find_set(par[u]);
}
void dfs(int u) {
int v, i;
num[u] = low[u] = ++tim;
for (ii pp : adj[u]) {
tie(v, i) = pp;
if (v == u) continue;
if (num[v]) {
if (p[0][v] == u) bri[v] = 0;
if (v != p[0][u])
low[u] = min(low[u], num[v]);
}
else {
d[v] = d[u] + 1; pred[v] = i;
p[0][v] = u; dfs(v);
low[u] = min(low[u], low[v]);
if (low[v] > num[u])
bri[v] = 1;
}
}
}
int lca(int u, int v) {
if (d[u] < d[v]) swap(u, v);
for (int k = LG - 1; ~k; k--)
if (d[p[k][u]] >= d[v])
u = p[k][u];
if (u == v) return u;
for (int k = LG - 1; ~k; k--)
if (p[k][u] != p[k][v]) {
u = p[k][u]; v = p[k][v];
}
return p[0][u];
}
int main() {
ios::sync_with_stdio(0);
cin.tie(nullptr);
int n, m; cin >> n >> m;
for (int i = 0; i < m; i++) {
cin >> ed[i].u >> ed[i].v;
adj[ed[i].u].eb(ed[i].v, i);
adj[ed[i].v].eb(ed[i].u, i);
}
iota(par + 1, par + n + 1, 1);
for (int i = 1; i <= n; i++)
if (!num[i]) dfs(i);
for (int k = 1; k < LG; k++)
for (int i = 1; i <= n; i++)
p[k][i] = p[k - 1][p[k - 1][i]];
int q; cin >> q;
while (q--) {
int u, v; cin >> u >> v;
int r = lca(u, v);
u = find_set(u);
while (d[u] > d[r]) {
if (bri[u]) col[pred[u]] = -1;
par[u] = p[0][u];
u = find_set(u);
}
v = find_set(v);
while (d[v] > d[r]) {
if (bri[v]) col[pred[v]] = 1;
par[v] = p[0][v];
v = find_set(v);
}
}
for (int i = 1; i <= n; i++)
if (bri[i] && ed[pred[i]].v != i)
col[pred[i]] *= -1;
for (int i = 0; i < m; i++) {
if (!col[i]) cout << 'B';
if (col[i] == 1) cout << 'R';
if (col[i] == -1) cout << 'L';
}
}
