#include<bits/stdc++.h>
using namespace std;
const int MAXN = 1e5 + 10;
const int MAXK = 23;
int marc[MAXN], tin[MAXN], low[MAXN], comp[MAXN], T;
struct edge{
int tipo;
int u, v;
void maketype(int mu, int mv, bool isont){
// printf("%d %d %d %d %d\n", mu, mv, isont,u, v );
if(mu == 0){
tipo = 3;
return;
}
if(!isont){
if(mu == u ) tipo = 1;
else tipo = 2;
}else{
if(mu == comp[u]) tipo = 1;
else tipo = 2;
}
}
}edges[MAXN];
vector<pair<int, int> > grafo[MAXN], grafosemponte[MAXN];
vector<int> bridge;
void makebridge( int id, int isbridge){
if(!isbridge) edges[id].maketype(0,0,0);
else{
bridge.push_back(id);
}
}
void dfsini(int x, int idp){
marc[x] = 1;
tin[x] = low[x] = ++T;
for(int i = 0; i < grafo[x].size(); i++){
int viz = grafo[x][i].first;
int id = grafo[x][i].second;
if(id == idp) continue;
if(marc[viz]) low[x] = min(tin[viz], low[x]);
else{
dfsini(viz, id);
makebridge(id, low[viz] > tin[x]);
low[x] = min(low[x], low[viz]);
}
}
}
int cmp;
void dfssec(int x){
comp[x] = cmp;
for(int i = 0; i < grafosemponte[x].size(); i++){
int viz = grafosemponte[x][i].first;
if(comp[viz]) continue;
dfssec(viz);
}
}
vector<pair<int, int> > tree[MAXN];
int dp[MAXN][MAXK], hasup[MAXN], minlcup[MAXN], hasdown[MAXN], minlcdown[MAXN];
int tintree[MAXN], altura[MAXN] ,Tt;
int marctree[MAXN];
void dfstree(int x, int p){
marctree[x] = 1;
tintree[x] = ++Tt;
minlcup[x] = minlcdown[x] = 1e9 + 7;
dp[x][0] = p;
for(int k = 1; k < MAXK; k++){
dp[x][k] = dp[dp[x][k-1]][k-1];
}
for(int i = 0; i < tree[x].size(); i++){
int viz = tree[x][i].first;
if(viz == p) continue;
altura[viz] = altura[x] + 1;
dfstree(viz, x);
}
}
void dfsprecalc(int x, int p){
marctree[x] = 2;
for(int i = 0; i < tree[x].size(); i++){
int viz = tree[x][i].first;
if(viz == p) continue;
dfsprecalc(viz, x);
hasdown[x] |= hasdown[viz];
hasup[x] |= hasup[viz];
if(hasup[viz]) minlcup[x] = min(minlcup[x], minlcup[viz]);
if(hasdown[viz]) minlcdown[x] = min(minlcdown[x], minlcdown[viz]);
}
}
void dfscalc(int x, int p){
marctree[x] = 3;
for(int i = 0; i < tree[x].size(); i++){
int viz = tree[x][i].first;
int id = tree[x][i].second;
if(viz == p) continue;
dfscalc(viz, x);
//printf("AQU: %d %d %d\n", viz, minlcdown[viz], minlcup[viz]);
if(hasup[viz] && minlcup[viz] <= tin[x]){
edges[id].maketype(viz, x,1);
}
else if(hasdown[viz] && minlcdown[viz] <= tin[x]){
edges[id].maketype(x, viz,1);
}else{edges[id].maketype(0,0,1);}
}
}
int lca(int u, int v){
if(altura[u] < altura[v]) swap(u,v);
int dist = altura[u] - altura[v];
for(int k = 0; k < MAXK; k++){
if(dist & (1<<k)) u = dp[u][k];
}
if(u == v) return u;
for(int k = MAXK - 1; k >= 0; k--){
if(dp[u][k] == dp[v][k]) continue;
u = dp[u][k];
v = dp[v][k];
}
return dp[u][0];
}
int n, m, p;
int main(){
scanf("%d %d", &n, &m);
for(int i = 1; i <= m; i++){
int u, v;
scanf("%d %d", &u, &v);
edges[i].u = u;
edges[i].v = v;
grafo[u].push_back(make_pair(v, i));
grafo[v].push_back(make_pair(u, i));
}
for(int i = 1; i <= n; i++){
if(!marc[i]) dfsini(i, 0);
}
for(int i = 1; i <= m; i++){
if(edges[i].tipo == 3){
grafosemponte[edges[i].u].push_back(make_pair(edges[i].v, 0));
grafosemponte[edges[i].v].push_back(make_pair(edges[i].u, 0));
}
}
for(int i = 1; i <= n; i++){
if(!comp[i])cmp++, dfssec(i);
}
for(int i = 0; i < bridge.size(); i++){
int u = edges[bridge[i]].u;
int v = edges[bridge[i]].v;
tree[comp[u]].push_back(make_pair(comp[v], bridge[i]));
tree[comp[v]].push_back(make_pair(comp[u], bridge[i]));
}
for(int i = 1; i <= cmp; i++){
if(!marctree[i]) Tt = 0, dfstree(i, 0);
}
scanf("%d", &p);
//memset(min)
for(int i = 0; i < p; i++){
int u, v;
scanf("%d %d", &u, &v);
if(comp[u] == comp[v]) continue;
u = comp[u];
v = comp[v];
int lc = lca(u,v);
// printf("LC: %d %d %d\n",u, v, lc );
if(lc == u){
hasdown[v] = 1;
minlcdown[v] = min(minlcdown[v], tintree[u]);
}else if(lc == v){
hasup[u] = 1;
minlcup[u] = min(minlcup[u], tintree[v]);
}else{
hasdown[v] = 1;
minlcdown[v] = min(minlcdown[v], tintree[lc]);
hasup[u] = 1;
minlcup[u] = min(minlcup[u], tintree[lc]);
}
}
for(int i = 1; i <= cmp; i++){
if(marctree[i] != 2) dfsprecalc(i, 0);
}
for(int i = 1; i <= cmp; i++){
if(marctree[i] != 3) dfscalc(i, 0);
}
for(int i = 1; i <= m; i++){
if(edges[i].tipo == 3 || edges[i].tipo == 0) printf("B");
if(edges[i].tipo == 2) printf("L");
if(edges[i].tipo == 1) printf("R");
}
printf("\n");
}
