#include <bits/stdc++.h>
using namespace std;
#define all(v) v.begin(),v.end()
#define eb push_back
#define ll long long
#define fi first
#define se second
int t,n,i,m,j,u,v,q;
const int maxn = 1e5 + 10,maxv = 20;
struct bruh
{
int XX,XXX,XXXX;
};
vector<bruh> a[maxn];
bool c[maxn],e[maxn],need[maxn];
int low[maxn],de[maxn],tim[maxn],ans[maxn],p[maxn][maxv];
set<int> from[maxn],to[maxn];
void dfs(int i,int pa)
{
low[i] = tim[i] = ++t;
c[i] = 1;
de[i] = de[pa]+1;
for(auto [k,id,ch] : a[i])
{
if(k == pa)continue;
if(c[k])low[i] = min(low[i],tim[k]);
else
{
dfs(k,i);
low[i] = min(low[i],low[k]);
p[k][0] = i;
if(low[k] > tim[i])need[id] = 1;
}
}
}
int lift(int i,int tmp)
{
for(int j = 0;j<maxv;j++)
{
if((tmp >> j)&1)i = p[i][j];
}
return i;
}
int lca(int i,int j)
{
if(de[i] < de[j])swap(i,j);
i = lift(i,de[i] - de[j]);
if(i == j)return i;
for(int k = maxv-1;k>=0;k--)
{
if(p[i][k] != p[j][k])
{
i = p[i][k];
j = p[j][k];
}
}
return p[i][0];
}
void solve(int i,int pa)
{
e[i] = 1;
// cout<<i<<' '<<pa<<'\n';
for(auto [k,id,ch]: a[i])
{
if(k == pa)continue;
if(!e[k])
{
solve(k,i);
if(need[id])
{
if(from[k].size())ans[id] = ch;
else if(to[k].size())ans[id] = 3- ch;
}
if(to[i].size() < to[k].size())swap(to[i],to[k]);
if(from[i].size() < from[k].size())swap(from[i],from[k]);
for(int l : from[k]) from[i].insert(l);
for(int l : to[k]) to[i].insert(l);
}
}
from[i].erase(de[i]);
to[i].erase(de[i]);
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(0);
cin>>n>>m;
for(i = 0;i<m;i++)
{
cin>>u>>v;
a[u].eb({v,i,1});
a[v].eb({u,i,2});
}
for(i = 1;i<=n;i++)
{
t = 0;
if(!c[i])dfs(i,0);
}
for(j = 1;j<maxv;j++)
{
for(i = 1;i<=n;i++)
{
p[i][j] = p[p[i][j-1]][j-1];
}
}
cin>>q;
while(q--)
{
cin>>u>>v;
int tmp = lca(u,v);
// cout<<tmp<<'\n';
if(u != tmp) to[u].insert(de[tmp]);
if(v != tmp) from[v].insert(de[tmp]);
}
for(i = 1;i<=n;i++)
{
if(!e[i])solve(i,0);
}
for(i = 0;i<m;i++)
{
if(ans[i] == 0)cout<<'B';
else if(ans[i] == 1)cout<<'R';
else cout<<'L';
}
return 0;
}
