#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pll pair<int, int>
#define mp make_pair
#define pb push_back
#define f first
#define s second
#define endl '\n'
#define ld long double
signed main(){
int n,m;cin>>n>>m;
vector<vector<pair<int,int>>> al(n+1);
vector<int> ord(n+1, -1), low(n+1, 1e9), out(n+1);
vector<array<int, 2>> ed(m+1);
for(int i=0;i<m;i++){
int a,b;cin>>a>>b;
ed[i][0]=a, ed[i][1]=b;
al[a].pb({i, 1});
al[b].pb({i, 0});
}
int q; cin >> q;
int t=0;
vector<vector<pair<int,int>>> ep(n+1);
vector<pair<int,int>> mn(n+1, {1e9, 0}), mx(n+1, {-1, 0});
for(int i=0;i<q;i++){
int a, b;cin>>a>>b;
ep[a].pb({b, 0ll});
ep[b].pb({a, 1ll});
}
auto dfs1 = [&](auto dfs1, int x, int p) -> void{
ord[x]=t;
low[x]=min(low[x], t);
t++;
//~ cout<<x<<endl;
for(auto [e, d]:al[x]){
if(e==p)continue;
if(ord[ed[e][d]] != -1)low[x]=min(low[x], ord[ed[e][d]]);
else {
dfs1(dfs1, ed[e][d], e);
}
}
out[x]=t-1;
};
dfs1(dfs1, 1, m);
//~ return 0;
vector<bool> vis(n+1, 0);
vector<int> ans(m+1, -1);
auto dfs2 = [&](auto dfs2, int x, int p) -> void{ // p is parent edge,
vis[x]=true;
bool up=(ed[p][0]==x);
for(auto [point, dir] : ep[x]){
//~ printf("%lld : point %lld dir %lld , ord %lld\n", x, point,dir,ord[point]);
mn[x]=min(mn[x], mp(ord[point], dir));
mx[x]=max(mx[x], mp(ord[point], dir));
}
for(auto [e, i] : al[x]){
int to=ed[e][i];
if(vis[ed[e][i]])continue;
dfs2(dfs2,to, e);
mn[x]=min(mn[x], mn[to]);
mx[x]=max(mx[x], mx[to]);
}
//~ printf("at %lld parent edge index %lld, ord %lld, out %lld, low %lld\n", x, p, ord[x], out[x], low[x]);
//~ printf("mn %lld %lld, mx %lld %lld\n", mn[x].f, mn[x].s, mx[x].f,mx[x].s);
if(low[x] < ord[x])ans[p]=-1;
else {
if(mn[x].f < ord[x]){
ans[p]=up ^ mn[x].s;
}
else if(mx[x].f > out[x]){
ans[p]=up ^ mx[x].s;
}
else {
ans[p]=-1;
}
}
};
dfs2(dfs2, 1, m);
for(int i=0;i<m;i++){
//~ cout<<ans[i]<<endl;
if(ans[i]==0)cout<<'L';
else if (ans[i]==1)cout<<'R';
else cout<<'B';
//~ else assert(false);
}
}
