#include <bits/stdc++.h>
using namespace std;
//#define FILE_IO
typedef pair<int, int> pii;
pii edge[100005];
int N, M, K;
int node[100005];
char r[100005];
namespace BiconnexGraph
{
int h[100005], low[100005], f[100005];
bool vis[100005], crit[100005];
vector<int> edg[100005];
void addEdge(int id)
{
int x = edge[id].first, y = edge[id].second;
edg[x].push_back(id);
edg[y].push_back(id);
}
int F(int x)
{
if(f[x] == x) return x;
return f[x] = F(f[x]);
}
void DFS(int nod, int id)
{
int fth = edge[id].first ^ edge[id].second ^ nod;
h[nod] = h[fth] + 1;
low[nod] = h[nod];
for(auto e: edg[nod])
{
if(e == id) continue;
int nxt = edge[e].first ^ edge[e].second ^ nod;
if(low[nxt] != 0)
{
low[nod] = min(low[nod], low[nxt]);
continue;
}
DFS(nxt, e);
low[nod] = min(low[nod], low[nxt]);
if(low[nxt] > h[nod])
crit[e] = 1;
}
}
void unite(int x, int y)
{
if(F(x) == F(y)) return;
f[F(y)] = F(x);
}
void uniteDFS(int nod)
{
if(vis[nod]) return;
vis[nod] = 1;
for(auto e: edg[nod])
{
int nxt = edge[e].first ^ edge[e].second ^ nod;
if(!crit[e])
{
uniteDFS(nxt);
unite(nod, nxt);
}
}
}
void compressGraph()
{
for(int i = 1; i <= N; i++)
if(!low[i])
DFS(i, 0);
for(int i = 1; i <= N; i++) f[i] = i;
for(int i = 1; i <= N; i++) uniteDFS(i);
for(int i = 1; i <= N; i++) node[i] = F(i);
}
}
namespace TreeGraph
{
vector<int> edg[100005];
int E, eul[100005], h[100005], f[100005], lg2[200005], up[2][100005], upedge[100005], rmq[19][200005];
char r[100005];
bool vis[100005];
void addEdge(int id)
{
int x = node[ edge[id].first ], y = node[ edge[id].second ];
edge[id].first = x, edge[id].second = y;
edg[x].push_back(id);
edg[y].push_back(id);
}
void DFS(int nod, int fth)
{
vis[nod] = 1;
f[nod] = fth;
h[nod] = h[fth] + 1;
rmq[0][++E] = nod;
eul[nod] = E;
up[0][nod] = up[1][nod] = nod;
for(auto e: edg[nod])
{
int nxt = edge[e].first ^ edge[e].second ^ nod;
if(nxt == fth) continue;
upedge[nxt] = e;
DFS(nxt, nod);
rmq[0][++E] = nod;
}
}
int minh(int a, int b)
{
if(h[a] < h[b]) return a;
return b;
}
int LCA(int a, int b)
{
int pa = eul[a], pb = eul[b];
if(pa > pb) swap(pa, pb);
int pw = lg2[pb - pa + 1];
return minh(rmq[pw][pa], rmq[pw][pb - (1 << pw) + 1]);
}
void pre()
{
for(int i = 1; i <= N; i++)
if(node[i] == i && !vis[i])
DFS(i, 0);
for(int i = 2; i <= E; i++)
{
lg2[i] = lg2[i - 1];
if( (2 << lg2[i]) == i ) lg2[i]++;
}
for(int i = 1; (1 << i) <= E; i++)
for(int j = 1; j + (1 << i) - 1 <= E; j++)
rmq[i][j] = minh(rmq[i - 1][j], rmq[i - 1][j + (1 << (i - 1))]);
}
int UP(int dir, int x)
{
if(up[dir][x] == x) return x;
return up[dir][x] = UP(dir, up[dir][x]);
}
void go(int x, int y, int dir)
{
if(h[x] <= h[y]) return;
if(UP(dir, x) == x)
{
up[dir][x] = UP(dir, f[x]);
pii e = (dir == 0 ? make_pair(x, f[x]) : make_pair(f[x], x));
r[ upedge[x] ] = (e == edge[ upedge[x] ] ? 'R' : 'L');
}
go(UP(dir, x), y, dir);
}
void go(int x, int y)
{
int lca = LCA(x, y);
go(x, lca, 0);
go(y, lca, 1);
}
}
int main()
{
#ifdef FILE_IO
freopen("1.in", "r", stdin);
freopen("1.out", "w", stdout);
#endif
scanf("%d%d", &N, &M);
for(int i = 1; i <= M; i++)
{
int x, y;
scanf("%d%d", &x, &y);
edge[i] = {x, y};
BiconnexGraph::addEdge(i);
}
BiconnexGraph::compressGraph();
for(int i = 1; i <= M; i++)
if(BiconnexGraph::crit[i])
{
int x = node[ edge[i].first ];
int y = node[ edge[i].second ];
TreeGraph::addEdge(i);
}
TreeGraph::pre();
scanf("%d", &K);
for(int i = 1; i <= K; i++)
{
int x, y;
scanf("%d%d", &x, &y);
if(node[x] == node[y]) continue;
x = node[x]; y = node[y];
TreeGraph::go(x, y);
}
for(int i = 1; i <= M; i++)
{
if(!BiconnexGraph::crit[i]) r[i] = 'B';
else if(TreeGraph::r[i]) r[i] = TreeGraph::r[i];
else r[i] = 'B';
}
printf("%s\n", r + 1);
return 0;
}
