#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> ii;
typedef pair<ld,ld> id;
#define FOR(i, a, b) for(int i=(a); i<=(b); i++)
#define ROF(i, a, b) for(int i=(a); i>=(b); i--)
#define MEM(x, v) memset(x, v, sizeof(x))
#define FILL(x, n, v) fill(x, x+n, v);
#define ALL(x) x.begin(), x.end()
#define SORT(x) sort((x).begin(), (x).end())
#define CMPSORT(x, cp) sort((x).begin(), (x).end(), cp)
#define FAST ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define f first
#define s second
#define ins insert
#define e emplace
#define eb emplace_back
#define ef emplace_front
#define p push
#define pf push_front
#define pb push_back
#define mp make_pair
#define ub upper_bound
#define lb lower_bound
#define ft front
#define bk back
#define pp pop
#define ppb pop_back
#define ppf pop_front
#define db cout<<"YEET\n";
#define ct(x) cout<<x<<'\n';
const ll MOD = 1e9+7; //998244353
const ll MAXN = 1e5+5;
const ll INF = 1e18;
const ld PI = acos((ld)-1);
ll n, m, p, a, b, idx;
ll ind[MAXN], low[MAXN], cycleID[MAXN], cyclecnt=0;
vector<ll> in_stack;
vector<tuple<ll, ll, char> > adjlist[MAXN]; //nextnode, id, left or right
vector<tuple<ll, ll, char> > cact[MAXN];
char edges[MAXN];
void dfs(ll u, ll idd){
low[u] = ind[u] = ++idx;
in_stack.pb(u);
for (auto edge : adjlist[u]){
ll v = get<0>(edge);
if (ind[v] == 0){ //node not visited
dfs(v, get<1>(edge));
low[u] = min(low[u], low[v]);
if (low[v] > ind[u]) edges[get<1>(edge)] = '-'; //is bridge
} else if (get<1>(edge) != idd) { //back edge to v
low[u] = min(low[u], ind[v]);
}
}
if (ind[u] == low[u]){
cyclecnt++;
while (1){
cycleID[in_stack.bk()] = cyclecnt;
if (in_stack.bk() == u) break;
in_stack.ppb();
}
in_stack.ppb();
}
}
ll visited[MAXN], depth[MAXN];
vector<tuple<ll, ll, char> > prevedge(MAXN);
ll par[18][MAXN];
void lcainit(ll u, ll dep){
visited[u] = 1;
depth[u] = dep;
for (auto edge : cact[u]){
ll v = get<0>(edge);
if (!visited[v]){
par[0][v] = u;
prevedge[v] = edge;
lcainit(v, dep+1);
}
}
}
void parinit(){
FOR(i,1,17){
FOR(j,1,n){
par[i][j] = par[i-1][par[i-1][j]];
}
}
}
ll lca(ll a, ll b){
if (depth[a] < depth[b]) swap(a,b);
ll diff = depth[a] - depth[b];
ll cnt=0;
while (diff){
if (diff&1) a = par[cnt][a];
cnt++;
diff>>=1;
}
if (a==b) return a;
ROF(i,17,0){
if (par[i][a] != par[i][b]){
a = par[i][a];
b = par[i][b];
}
}
return par[0][a];
}
int main(){
FAST
cin >> n >> m;
FOR(i,1,m){
cin >> a >> b;
adjlist[a].eb(b,i,'R');
adjlist[b].eb(a,i,'L');
}
MEM(edges, 'B');
FOR(i,1,n){
if (ind[i] == 0){
dfs(i, -1);
}
}
FOR(i,1,n){
ll sz = adjlist[i].size()-1;
FOR(j,0,sz){
ll u = i;
ll v, idd;
char dir;
tie(v,idd,dir) = adjlist[i][j];
if (cycleID[u] != cycleID[v]) cact[cycleID[u]].eb(cycleID[v],idd,dir);
}
}
FOR(i,1,cyclecnt){
if (!visited[i]) {
par[0][i] = i;
lcainit(i,0);
}
}
parinit();
cin >> p;
vector<tuple<ll,ll,ll,ll> > pairs; // depth, u, v, ancestor
FOR(i,1,p){
cin >> a >> b;
a = cycleID[a];
b = cycleID[b];
ll anc = lca(a,b);
pairs.eb(depth[anc], a, anc, anc);
pairs.eb(depth[anc], anc, b, anc);
}
sort(ALL(pairs));
for (auto pr : pairs){
ll u = get<1>(pr);
ll v = get<2>(pr);
ll ancestor = get<3>(pr);
while (u != ancestor){
ll idd = get<1>(prevedge[u]);
ll dirc = get<2>(prevedge[u]);
if (edges[idd] != '-') break;
else {
if (dirc == 'R') edges[idd] = 'L';
else edges[idd] = 'R';
u = par[0][u];
}
}
while (v != ancestor){
ll idd = get<1>(prevedge[v]);
ll dirc = get<2>(prevedge[v]);
if (edges[idd] != '-') break;
else {
if (dirc == 'R') edges[idd] = 'R';
else edges[idd] = 'L';
v = par[0][v];
}
}
}
FOR(i,1,m){
if (edges[i] == '-') cout << "B";
else cout << edges[i];
}
}
