#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 5;
vector<pair<int, int>> g[N];
int tin[N], low[N], timer;
bool isBridge[N];
int comp[N], compCnt;
vector<int> tree[N];
int par[N][17], depth[N];
map<pair<int, int>, int> bridgeToIndex;
struct Edge {
int u, v;
};
Edge edges[N];
int edgeDir[N];
void dfsBridge(int v, int p = -1, int pIdx = -1) {
tin[v] = low[v] = ++timer;
for (auto [to, idx] : g[v]) {
if (to == p && idx == pIdx) continue;
if (tin[to]) {
low[v] = min(low[v], tin[to]);
} else {
dfsBridge(to, v, idx);
low[v] = min(low[v], low[to]);
if (low[to] > tin[v]) {
isBridge[idx] = true;
}
}
}
}
void dfsComponent(int u, int c) {
comp[u] = c;
for (auto [v, idx] : g[u]) {
if (comp[v] == -1 && !isBridge[idx]) {
dfsComponent(v, c);
}
}
}
void dfsLCA(int u, int p) {
par[u][0] = p;
for (int i = 1; i < 17; ++i) {
if (par[u][i - 1] != -1)
par[u][i] = par[par[u][i - 1]][i - 1];
}
for (int v : tree[u]) {
if (v != p) {
depth[v] = depth[u] + 1;
dfsLCA(v, u);
}
}
}
int lca(int u, int v) {
if (depth[u] < depth[v]) swap(u, v);
for (int i = 16; i >= 0; --i)
if (par[u][i] != -1 && depth[par[u][i]] >= depth[v])
u = par[u][i];
if (u == v) return u;
for (int i = 16; i >= 0; --i)
if (par[u][i] != -1 && par[u][i] != par[v][i])
u = par[u][i], v = par[v][i];
return par[u][0];
}
void mark(int u, int v, int up) {
while (u != v) {
int p = par[u][0];
int a = u, b = p;
if (a > b) swap(a, b);
int idx = bridgeToIndex[{a, b}];
if (up) edgeDir[idx] |= 1;
else edgeDir[idx] |= 2;
u = p;
}
}
int main() {
ios::sync_with_stdio(0); cin.tie(0);
int n, m; cin >> n >> m;
for (int i = 0; i < m; ++i) {
int u, v; cin >> u >> v;
--u, --v;
g[u].emplace_back(v, i);
g[v].emplace_back(u, i);
edges[i] = {u, v};
}
dfsBridge(0);
fill(comp, comp + n, -1);
compCnt = 0;
for (int i = 0; i < n; ++i) {
if (comp[i] == -1) dfsComponent(i, compCnt++);
}
int id = 0;
for (int i = 0; i < m; ++i) {
if (isBridge[i]) {
int a = comp[edges[i].u];
int b = comp[edges[i].v];
tree[a].push_back(b);
tree[b].push_back(a);
int u = min(a, b), v = max(a, b);
bridgeToIndex[{u, v}] = id++;
}
}
memset(par, -1, sizeof par);
dfsLCA(0, -1);
int p; cin >> p;
while (p--) {
int u, v; cin >> u >> v;
u = comp[--u]; v = comp[--v];
int w = lca(u, v);
mark(u, w, 1);
mark(v, w, 0);
}
string res;
for (int i = 0; i < m; ++i) {
if (!isBridge[i]) {
res += 'B';
} else {
int a = comp[edges[i].u];
int b = comp[edges[i].v];
int u = min(a, b), v = max(a, b);
int idx = bridgeToIndex[{u, v}];
int cu = comp[edges[i].u], cv = comp[edges[i].v];
if (edgeDir[idx] == 1) {
if (cu == a && cv == b) res += 'R';
else res += 'L';
} else if (edgeDir[idx] == 2) {
if (cu == a && cv == b) res += 'L';
else res += 'R';
} else {
res += 'B';
}
}
}
cout << res << '\n';
return 0;
}
