#include <bits/stdc++.h>
#define IO ios::sync_with_stdio(false);cin.tie(0);
#define debug(x) cerr << #x << " = " << (x) << ' '
#define bug(x) cerr << (x) << ' '
#define endl cerr << '\n'
#define all(v) (v).begin(), (v).end()
#define SZ(v) (ll)(v).size()
#define lowbit(x) (x)&-(x)
#define pb emplace_back
#define F first
#define S second
using namespace std;
using ll = long long;
using pll = pair<ll, ll>;
const int N = 1e5+5;
const int LogN = 17;
int dfn[N], low[N], timer, tag[LogN+5][N], tin[N],
tout[N], anc[LogN+5][N];
pll e[N];
bool cut[N];
vector<pll> g[N];
vector<int> tr[N];
inline void tarjan(int x, int pid)
{
dfn[x] = low[x] = ++timer;
for (auto e : g[x])
{
int v = e.F, id = e.S;
if (id == pid) continue;
if (!dfn[v])
{
tarjan(v, id);
tr[x].pb(v), tr[v].pb(x);
low[x] = min(low[x], low[v]);
} else {
low[x] = min(low[x], dfn[v]);
}
if (low[v] > dfn[x]) cut[id] = 1;
}
}
inline bool is_anc(int x, int y)
{ return tin[x] < tin[y] && tout[y] < tout[x]; }
inline void dfs(int x, int pre)
{
tin[x] = ++timer, anc[0][x] = pre;
for (int v : tr[x]) if (v != pre) dfs(v, x);
tout[x] = ++timer;
}
inline int get_lca(int x, int y)
{
if (is_anc(x, y)) return x;
if (is_anc(y, x)) return y;
for (int i=LogN; i >= 0; --i)
if (anc[i][x] && !is_anc(anc[i][x], y)) x = anc[i][x];
return anc[0][x];
}
inline void update(int x, int y, int c)
{
for (int i=LogN; i >= 0; --i)
{
if (anc[i][x] && !is_anc(anc[i][x], y))
tag[i][x] |= c, x = anc[i][x];
}
}
int main(void)
{ IO
int n, i, m, Q;
cin >> n >> m;
for (i=1; i <= m; ++i)
{
int x, y; cin >> x >> y, e[i] = {x, y};
g[x].pb(y, i), g[y].pb(x, i);
}
for (i=1; i <= n; ++i)
{
if (!dfn[i])
{
tarjan(i, 0);
dfs(i, 0);
}
}
for (i=1; i <= LogN; ++i)
for (int j=1; j <= n; ++j) anc[i][j] = anc[i-1][anc[i-1][j]];
cin >> Q;
do {
int x, y; cin >> x >> y;
int tmp = get_lca(x, y);
update(x, tmp, 1), update(y, tmp, 2);
} while (--Q);
for (i=LogN; i > 0; --i)
{
for (int j=1; j <= n; ++j)
{
tag[i-1][j] |= tag[i][j];
tag[i-1][anc[i-1][j]] |= tag[i][j];
}
}
for (i=1; i <= m; ++i)
{
if (!cut[i]) cout << "B";
else {
int x = e[i].F, y = e[i].S;
if (x == y) continue;
if (tin[x] < tin[y]) swap(x, y);
if (tag[0][x] == 3) assert(0);
if (tag[0][x] == 1)
{
if (x == e[i].F) cout << "R";
else cout << "L";
} else if (tag[0][x] == 2) {
if (x == e[i].F) cout << "L";
else cout << "R";
} else {
cout << "B";
}
}
}
cout << '\n';
return 0;
}
