#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define ll int
typedef pair<ll,ll> pi;
typedef vector <ll> vi;
typedef vector <pi> vpi;
typedef pair<pi, ll> pii;
typedef set <ll> si;
typedef long double ld;
#define f first
#define s second
#define mp make_pair
#define FOR(i,s,e) for(int i=s;i<=int(e);++i)
#define DEC(i,s,e) for(int i=s;i>=int(e);--i)
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define lbd(x, y) lower_bound(all(x), y)
#define ubd(x, y) upper_bound(all(x), y)
#define aFOR(i,x) for (auto i: x)
#define mem(x,i) memset(x,i,sizeof x)
#define fast ios_base::sync_with_stdio(false),cin.tie(0),cout.tie(0)
#define MOD 1000000007
#define maxn 100010
#define INF (ll)1e18
int TC;
int N,M;
vi adj[maxn];
int low[maxn], disc[maxn], grp[maxn], num = 1;
stack <int> s; bool onstack[maxn]; //disc is discovery time
int ans[maxn], counter = 1;
void dfs(int x, int p) {
disc[x] = low[x] = counter++;
s.push(x);
onstack[x] = true; int co = 0;
for (auto i: adj[x]) {
if (i == p){
co++;
if (co > 1){
low[x] = min(low[x],disc[i]);
}
continue;
}
if (disc[i] == -1) {
dfs(i,x);
low[x] = min(low[x],low[i]);
} else if (onstack[i]) {
low[x] = min(low[x],disc[i]);
}
}
if (disc[x] == low[x]) {
int cur;
while (1) {
cur = s.top();
s.pop();
onstack[cur] = false;
grp[cur] = num;
if (cur == x) break;
}
num++;
}
}
int P, X[maxn], Y[maxn];
vpi Z[maxn];
unordered_set <int> st[maxn];
void insert(int i, int x,int y){
int a = x + y*P, b = x + (!y) * P;
if (st[i].find(b) != st[i].end()){
st[i].erase(b); //co[!y]--;
}else{
st[i].insert(a); //co[y]++;
}
}
int ans2[maxn], par[maxn];
bool vis[maxn];
void findans(int x, int p){ //set merging
int mx = -1; par[x] = p;
assert(!vis[x]);
vis[x] = 1;
aFOR(i,adj[x]) if (i != p){
findans(i, x);
if (mx == -1 || st[mx].size() < st[i].size()) mx = i;
}
if (mx != -1) st[x].swap(st[mx]);
aFOR(i,Z[x]) insert(x, i.f, i.s);
aFOR(i,adj[x]) if (i != p && i != mx){
aFOR(j, st[i]){
int z = j; bool y = 0;
if (j > P){z -= P; y = 1;}
insert(x, z, y);
}
st[i].clear();
}
//~ assert(st[x].co[0] == 0 || st[x].co[1] == 0);
if (st[x].empty()) ans2[x] = 2;
else if (*st[x].begin() <= P) ans2[x] = 0; // upward
else ans2[x] = 1; // downward
//~ else
//~ else assert(0);
}
int32_t main() {
fast;
mem(ans,-1);
cin >> N >> M;
vpi edges;
int a,b;
FOR(i,1,M){
cin >> a >> b; adj[a].pb(b); adj[b].pb(a);
edges.pb(pi(a,b));
}
cin >> P;
FOR(i,1,P){
cin >> X[i] >> Y[i];
}
mem(disc,-1);
FOR(i,1,N) if (disc[i] == -1) dfs(i,-1);
FOR(i,1,N) adj[i].clear();
//~ FOR(i,1,N) cout << grp[i] << ' ';
//~ cout << '\n';
FOR(i,1,N) vis[i] = 0;
FOR(i,0,M-1){
if (grp[edges[i].f] == grp[edges[i].s]){
ans[i] = 2;
}else{
adj[grp[edges[i].f]].pb(grp[edges[i].s]);
adj[grp[edges[i].s]].pb(grp[edges[i].f]);
}
}
FOR(i,1,P){
int a = grp[X[i]], b = grp[Y[i]];
if (a != b){
Z[a].pb(pi(i, 0)); Z[b].pb(pi(i, 1));
}
}
mem(ans2,-1);
findans(1,-1);
FOR(i,1,num-1) if (!vis[i]) findans(i,-1);
FOR(i,0,M-1){
int a = grp[edges[i].f], b = grp[edges[i].s];
if (a != b){
int x;
if (par[a] == b) x = a;
else x = b;
assert(ans2[x] != -1);
if (ans2[x] == 2) ans[i] = 2;
else if (ans2[x] == 0){
if (x == a){ // a is child, a->b
ans[i] = 1;
}else ans[i] = 0;
}else{
if (x == a) ans[i] = 0;
else ans[i] = 1;
}
}
}
FOR(i,0,M-1){
if (ans[i] == 2) cout << 'B';
else if (ans[i] == 0) cout << 'L';
else cout << 'R';
}
}
