#include <bits/stdc++.h>
using namespace std;
#define int long long
#define rep(i,a,b) for (int i = a; i <= b; i++)
#define per(i,a,b) for (int i = a; i >= b; i--)
#define pii pair<int,int>
#define fi first
#define se second
#define endl '\n'
#define pb push_back
#define all(v) (v).begin(), (v).end()
const int MAXN = 1e3+10;
const int INF = 1e18+10;
const int MOD = 1e9+7;
vector<int> g[MAXN];
bool vis[MAXN][MAXN];
void dfs(int u,int head) {
if(vis[head][u]) return;
vis[head][u] = 1;
for(int &v : g[u]) dfs(v,head);
}
void solve() {
int n,m; cin >> n >> m;
vector<pii> e(m), imp;
string ans;
rep(i,1,m) ans+='a';
for(auto &x : e) cin >> x.fi >> x.se;
int p; cin >> p;
imp.resize(p);
for(auto &x : imp) cin >> x.fi >> x.se;
rep(mk,0,(1<<m)-1) {
rep(i,1,n) g[i].clear();
rep(i,1,n) rep(j,1,n) vis[i][j] = 0;
rep(i,0,m-1) {
int u = e[i].fi;
int v = e[i].se;
if(mk>>i&1) g[u].pb(v);
else g[v].pb(u);
}
rep(i,1,n) dfs(i,i);
bool ok = 1;
for(auto &[u,v] : imp) {
ok &= vis[u][v];
}
if(!ok) continue;
rep(i,0,m-1) {
char cur = 'L';
if(mk>>i&1) cur = 'R';
if(ans[i]=='a') {
ans[i] = cur;
continue;
}
if(ans[i]!=cur) {
ans[i] = 'B';
}
}
}
cout << ans << endl;
}
int32_t main() {
ios_base::sync_with_stdio(0);cin.tie(nullptr);
int tt = 1;
//cin >> tt;
while(tt--) solve();
}
