#include <bits/stdc++.h>
#define FOR(i, l, r) for(int i=(l); i<=(r); ++i)
#define REP(i, l, r) for(int i=(l); i<(r); ++i)
#define FORD(i, r, l) for(int i=(r); i>=(l); --i)
#define REPD(i, r, l) for(int i=(r)-1; i>=(l); --i)
#define pii pair<int, int>
#define getbit(x, i) (((x) >> (i)) & 1)
using namespace std;
const int N = 1e5 + 5, M = 1e5 + 5, logN = 18, Qmax = 1e5 + 5;
int n, m, q, cnt, cnode, px[M], py[M];
int depth[N], p[N][logN], sedge[N], pre[N], parent_pair[Qmax];
int num[N], low[N], avail[N], exist[N], node[N];
vector<pii> S[N], Scc[N];
vector<int> Q, D[N], List;
char ans[M];
void Enter() {
cin >> n >> m;
FOR(i, 1, m) {
int u, v;
cin >> u >> v;
S[u].emplace_back(v, i);
S[v].emplace_back(u, -i);
}
cin >> q;
FOR(i, 1, q) cin >> px[i] >> py[i];
}
void Tarjan(int u, int pre_edge) {
num[u] = low[u] = ++cnt;
Q.push_back(u);
for(auto [v, c] : S[u]) if (-c != pre_edge) {
if (num[v]) low[u] = min(low[u], num[v]);
else {
Tarjan(v, c);
low[u] = min(low[u], low[v]);
}
}
if (num[u] == low[u]) {
++cnode;
int v;
do {
v = Q.back(); Q.pop_back();
node[v] = cnode;
D[cnode].push_back(v);
} while (v != u);
}
}
void Compress() {
FOR(i, 1, n) if (!avail[i]) {
Tarjan(i, 0);
}
FOR(i, 1, cnode) {
exist[i] = i;
for(int u : D[i]) for(auto [v, c] : S[u]) if (exist[node[v]] != i) {
exist[node[v]] = i;
Scc[i].emplace_back(node[v], c);
}
}
}
void DFS2(int u, int pa) {
depth[u] = depth[pa] + 1;
List.push_back(u);
p[u][0] = pa;
REP(i, 1, logN) p[u][i] = p[p[u][i - 1]][i - 1];
for(auto [v, c] : Scc[u]) if (v != pa) {
sedge[v] = c;
DFS2(v, u);
}
}
int LCA(int u, int v) {
if (depth[u] > depth[v]) swap(u, v);
int diff = depth[v] - depth[u];
REPD(i, logN, 0) if (getbit(diff, i)) v = p[v][i];
REPD(i, logN, 0) if (p[u][i] != p[v][i]) u = p[u][i], v = p[v][i];
return (u == v ? u : p[u][0]);
}
void solve(char c1, char c2) {
REPD(i, (int) List.size(), 0) {
int u = List[i];
assert(pre[u] >= 0);
if (sedge[u] && pre[u]) {
if (sedge[u] > 0) ans[sedge[u]] = c1;
else ans[-sedge[u]] = c2;
}
pre[p[u][0]] += pre[u];
}
}
void Process() {
Compress();
FOR(i, 1, cnode) if (!depth[i]) DFS2(i, 0);
FOR(i, 1, q) {
int u = node[px[i]], v = node[py[i]];
parent_pair[i] = LCA(u, v);
}
fill(ans + 1, ans + m + 1, 'B');
FOR(i, 1, q) {
int u = node[px[i]];
++pre[u]; --pre[parent_pair[i]];
}
solve('L', 'R');
fill(pre + 1, pre + cnode + 1, 0);
FOR(i, 1, q) {
int u = node[py[i]];
++pre[u]; --pre[parent_pair[i]];
}
solve('R', 'L');
cout << ans + 1;
}
int main()
{
#define file "oneway"
if (fopen(file".inp", "r")) {
freopen(file".inp", "r", stdin);
freopen(file".out", "w", stdout);
}
ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
Enter();
Process();
}
