#include<bits/stdc++.h>
#ifdef LOCAL
#include "D:\debug.h"
#else
#define cebug(...) "Orz_chUoNgnn_khanhtb_0x2ee08"
#endif
using namespace std;
#define fi first
#define se second
#define pb push_back
#define ll long long
#define ii pair<int, int>
#define vi vector<int>
#define vll vector<ll>
#define vii vector<ii>
#define cd complex<double>
const ll mod = 1e9 + 7;
const ll INF = 1e18L + 5;
const double PI = acos(-1);
const int block = 320;
const int N = 2e5;
int tc, tt = 1;
int n, m, u, v, p;
ii ans[N + 5];
struct edge {
int v, id, x, y;
};
vector<edge> g[N + 5];
vii e;
namespace sub1 {
bool ck() {
return true;
}
int tin[N + 5], tout[N + 5], low[N + 5], tdfs = 0;
int p[N + 5][20];
int mark[N + 5];
int vis[N + 5];
int comp[N + 5], curcomp = 0;
bool bridge[N + 5];
int h[N + 5];
int dp[N + 5];
int s, t;
vector<edge> adj[N + 5];
void find_bridge(int u ,int par) {
tin[u] = low[u] = ++tdfs;
vis[u] = true;
for(auto v: g[u])
if(v.v != par) {
if(!vis[v.v]) {
find_bridge(v.v, u);
low[u] = min(low[u], low[v.v]);
if(low[v.v] > tin[u])
bridge[v.id] = true;
}
else low[u] = min(low[u], tin[v.v]);
}
tout[u] = tdfs;
}
void find_comp(int u, int par) {
vis[u] = true;
comp[u] = curcomp;
for(auto v: g[u])
if(v.v != par && !vis[v.v] && !bridge[v.id])
find_comp(v.v, u);
}
void dfs(int u, int par) {
vis[u] = true;
for(auto v: adj[u])
if(v.v != par) {
v.x = u;
v.y = v.v;
dfs(v.v, u);
}
}
void cal(int u, int par) {
vis[u] = true;
for(auto v: adj[u])
if(v.v != par) {
cal(v.v, u);
dp[u] += dp[v.v];
if(dp[v.v] > 0) ans[v.id] = {v.y, v.x};
if(dp[v.v] < 0) ans[v.id] = {v.x, v.y};
}
}
void sol() {
memset(vis, 0, sizeof(vis));
for(int i=1; i<=n; i++)
if(!vis[i]) {
tdfs = 0;
find_bridge(i, -1);
}
memset(vis, 0, sizeof(vis));
for(int i=1; i<=n; i++)
if(!vis[i]) {
curcomp++;
find_comp(i, -1);
}
for(int i=1; i<=m; i++)
if(bridge[i]) {
int u = e[i - 1].fi;
int v = e[i - 1].se;
if(comp[u] != comp[v]) {
adj[comp[u]].pb({comp[v], i, u, v});
adj[comp[v]].pb({comp[u], i, v, u});
}
}
memset(vis, 0, sizeof(vis));
for(int i=1; i<=n; i++)
if(!vis[i])
dfs(i, -1);
int q;
cin>>q;
for(int i=1; i<=q; i++) {
cin>>s>>t;
dp[comp[s]]++;
dp[comp[t]]--;
}
memset(vis, 0, sizeof(vis));
for(int i=1; i<=n; i++) {
if(!vis[i]) cal(i, -1);
}
for(int i=1; i<=m; i++) {
if(ans[i].fi < 0 || !bridge[i]) {
cout<<"B";
}
else {
cout<<(ans[i] == e[i - 1] ? "R" : "L");
}
}
}
}
void solve() {
cin>>n>>m;
for(int i=1; i<=m; i++) {
cin>>u>>v;
ans[i] = {-1, -1};
e.pb({u, v});
g[u].pb({v, i, -1, -1});
g[v].pb({u, i, -1, -1});
}
if(sub1::ck()) {sub1::sol(); return;}
}
signed main() {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
for(tc=1; tc<=tt; tc++) solve();
cerr<<"\nTime elapsed: "<<1000.0*clock()/CLOCKS_PER_SEC<<" ms.\n";
return 0;
}
