#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;
const int N = 100000;
const int M = 100000;
const int K = 100000;
vector<int> eh[N], ez[N];
int ii[M], jj[M], uu[K], vv[K], ta_[N], ta[N], tb[N];
char cc[M + 1];
void dfs(int i) {
if (ta_[i])
return;
static int t = 0;
ta_[i] = ++t;
for (int h : eh[i])
dfs(i ^ ii[h] ^ jj[h]);
}
pair<int, pair<int, int>> dfs(int h_, int i) {
static int t = 0;
ta[i] = ++t;
int p_ = i, zl_ = -1, zr_ = -1;
for (int h : eh[i])
if (h != h_) {
int j = i ^ ii[h] ^ jj[h];
if (!ta[j]) {
auto o = dfs(h, j); int p = o.first, zl = o.second.first, zr = o.second.second;
if (ta[p] < ta[j] || zl == -1 || ta[j] <= min(ta_[uu[zl]], ta_[vv[zl]]) && max(ta_[uu[zr]], ta_[vv[zr]]) <= tb[j])
cc[h] = 'B';
else
cc[h] = ii[h] == ((min(ta_[uu[zl]], ta_[vv[zl]]) < ta[j] ? ta_[uu[zl]] < ta[j] : ta_[uu[zr]] > tb[j]) ? i : j) ? 'R' : 'L';
if (ta[p_] > ta[p])
p_ = p;
if (zl != -1) {
if (zl_ == -1 || min(ta_[uu[zl_]], ta_[vv[zl_]]) > min(ta_[uu[zl]], ta_[vv[zl]]))
zl_ = zl;
if (zr_ == -1 || max(ta_[uu[zr_]], ta_[vv[zr_]]) < max(ta_[uu[zr]], ta_[vv[zr]]))
zr_ = zr;
}
} else {
cc[h] = 'B';
if (ta[p_] > ta[j])
p_ = j;
}
}
tb[i] = t;
for (int z : ez[i]) {
if (zl_ == -1 || min(ta_[uu[zl_]], ta_[vv[zl_]]) > min(ta_[uu[z]], ta_[vv[z]]))
zl_ = z;
if (zr_ == -1 || max(ta_[uu[zr_]], ta_[vv[zr_]]) < max(ta_[uu[z]], ta_[vv[z]]))
zr_ = z;
}
return { p_, { zl_, zr_ } };
}
int main() {
ios_base::sync_with_stdio(false), cin.tie(NULL);
#define task "task"
if(fopen(task".inp", "r")) {
freopen(task".inp", "r", stdin);
freopen(task".ans", "w", stdout);
}
int n, m; cin >> n >> m;
for (int h = 0; h < m; h++) {
int i, j; cin >> i >> j, i--, j--;
eh[ii[h] = i].push_back(h);
eh[jj[h] = j].push_back(h);
}
int k; cin >> k;
for (int z = 0; z < k; z++) {
int u, v; cin >> u >> v, u--, v--;
ez[uu[z] = u].push_back(z);
ez[vv[z] = v].push_back(z);
}
for (int i = 0; i < n; i++)
if (!ta[i])
dfs(i), dfs(-1, i);
cc[m] = '\0';
cout << cc << '\n';
return 0;
}
