#include <bits/stdc++.h>
#pragma GCC optimize ("O2,unroll-loops")
using namespace std;
typedef pair<int, int> pii;
#define pb push_back
const int MAXN = 100010;
int n, m, k, u, v, x, y, t, a, b;
int val[MAXN];
char ans[MAXN];
int E[MAXN][2];
int H[MAXN];
int comp[MAXN];
vector<pii> G[MAXN];
vector<int> G2[MAXN], bridge;
int Bridge(int node, int par, int parid){
int res=H[node]=H[par]+1;
for (pii p:G[node]) if (p.second!=parid){
int v=p.first, i=p.second;
if (H[v]){
res=min(res, H[v]);
ans[i]='B';
}
else res=min(res, Bridge(v, node, i));
}
if (res<H[node]){
ans[parid]='B';
G2[par].pb(node);
G2[node].pb(par);
}
else if (parid) bridge.pb(parid);
return res;
}
void dfs1(int node, int id){
comp[node]=id;
for (int v:G2[node]) if (!comp[v]) dfs1(v, id);
}
int dfs2(int node, int par, int parid){
H[node]=H[par]+1;
for (pii p:G[node]) if (p.first!=par) val[node]+=dfs2(p.first, node, p.second);
if (val[node]==0) ans[parid]='B';
else if (val[node]<0 ^ E[parid][0]==par) ans[parid]='L';
else ans[parid]='R';
return val[node];
}
int main(){
ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
//freopen("input.txt", "r", stdin);
//freopen("output.txt", "w", stdout);
cin>>n>>m;
for (int i=1; i<=m; i++){
cin>>u>>v;
E[i][0]=u, E[i][1]=v;
G[u].pb({v, i});
G[v].pb({u, i});
}
for (int i=1; i<=n; i++) if (!H[i]) Bridge(i, i, 0);
for (int i=1; i<=n; i++) if (!comp[i]) dfs1(i, i);
for (int i=1; i<=n; i++) G[i].clear();
for (int i:bridge){
E[i][0]=comp[E[i][0]];
E[i][1]=comp[E[i][1]];
int u=E[i][0], v=E[i][1];
G[u].pb({v, i});
G[v].pb({u, i});
}
cin>>k;
while (k--){
cin>>u>>v;
u=comp[u];
v=comp[v];
val[u]++;
val[v]--;
}
memset(H, 0, sizeof(H));
for (int i=1; i<=n; i++) if (!H[i]) dfs2(i, i, 0);
for (int i=1; i<=m; i++) cout<<ans[i];
return 0;
}
