#include<bits/stdc++.h>
using namespace std;
// define
#define execute cerr << " Time: " << fixed << setprecision(6) << (1.0 * clock() / CLOCKS_PER_SEC) << "s\n";
#define ll long long
#define ld double
#define ii pair<int,int>
#define se second
#define fi first
#define iii pair<int,ii>
#define all(v) v.begin(),v.end()
#define bit(x,i) (((x)>>(i))&1LL)
#define flip(x,i) ((x)^(1LL<<(i)))
#define ms(d,x) memset(d,x,sizeof(d))
#define sitingfake 1
#define orz 1
//constant
const ll mod = 1e9+7;
const long long linf = 4557430888798830399;
const int inf = 1061109567;
const int maxarr = 1e6+5;
const int dx[] = {0,1,-1,0};
const int dy[] = {1,0,0,-1};
template<typename T> bool maximize(T &a, const T &b)
{
if(a < b) {a = b; return 1;}
return 0;
}
template<typename T> bool minimize(T &a, const T &b)
{
if(a > b) {a = b; return 1;}
return 0;
}
inline void Plus(ll & a ,ll b)
{
a += b;
if(a >= mod) a -= mod;
if(a < 0) a += mod;
return;
}
inline void Mul(ll & a, ll b)
{
a %= mod; b %= mod;
a *= b;
a %= mod;
return;
}
//code
const int maxn = 1e5 + 7;
int tplt , scc[maxn] , low[maxn] , id[maxn] , timer;
int par[maxn][20] , depth[maxn],dp[maxn] , f[maxn];
bool visited[maxn];
ii edges[maxn];
vector <ii> a[maxn];
vector <iii> G[maxn]; // 0 = right , 1 = left;
stack <int> s;
char ans[maxn];
int n , m , k;
ii p[maxn];
void dfs(int u , int p)
{
low[u] = id[u] = ++ timer;
s.push(u);
for(ii i : a[u])
{
int v = i.fi;
int np = i.se;
if(p == np) continue;
if(!id[v])
{
dfs(v , np);
low[u] = min(low[u] , low[v]);
}
else low[u] = min(low[u] , id[v]);
}
if(low[u] == id[u])
{
int v;
++tplt;
do
{
v = s.top();
s.pop();
scc[v] = tplt;
} while(u != v);
}
}
void DFS(int u , int p)
{
visited[u] = 1;
for(iii i : G[u])
{
int v = i.se.fi;
if(v == p) continue;
depth[v] = depth[u] + 1;
par[v][0] = u;
DFS(v , u);
}
}
void Prepare()
{
for(int j = 1; (1 << j) <= tplt ;j ++)
{
for(int i = 1; i <= tplt ;i++)
{
par[i][j] = par[par[i][j-1]][j-1];
}
}
}
int lca(int u ,int v)
{
if(depth[u] < depth[v]) swap(u , v);
int diff = depth[u] - depth[v];
for(int i = 0 ; (1 << i) <= diff ; i++)
{
if(bit(diff , i))
{
u = par[u][i];
}
}
if(u == v) return u;
for(int i = 19; i >= 0 ; i--)
{
if(par[u][i] != par[v][i])
{
v = par[v][i];
u = par[u][i];
}
}
return par[u][0];
}
void Query(int u , int v)
{
int lc = lca(u , v);
dp[u] ^= 1;
dp[lc] ^= 1;
f[u] ++;
f[v] ++;
f[lc] -= 2;
}
void get(int u ,int p)
{
visited[u] = 1;
for(iii i : G[u])
{
int v = i.se.fi;
int id = i.se.se;
int val = i.fi;
if(v != p)
{
get(v , u);
if(f[v] > 0)
{
val ^= dp[v];
if(val == 0) ans[id] = 'R';
else ans[id] = 'L';
}
else ans[id] = 'B';
dp[u] ^= dp[v];
f[u] += f[v];
}
}
}
void solve(void)
{
cin >> n >> m;
for(int i = 1; i <= m ; i++)
{
int u , v;
cin >> u >> v;
a[u].push_back(ii(v , i));
a[v].push_back(ii(u , i));
edges[i] = ii(u , v);
}
cin >> k;
for(int i = 1; i <= k ;i++) cin >> p[i].fi >> p[i].se;
for(int i = 1; i <= n ; i++)
{
if(!id[i]) dfs(i , -1);
}
for(int i = 1; i <= m ;i++)
{
int u = scc[edges[i].fi] , v = scc[edges[i].se];
if(u == v)
{
ans[i] = 'B';
}
else
{
G[u].push_back(iii(0 , ii(v , i)));
G[v].push_back(iii(1 , ii(u , i)));
}
}
for(int i = 1; i <= tplt ; i++)
{
if(!visited[i])
{
DFS(i , -1);
}
}
Prepare();
for(int i = 1; i <= k ;i++)
{
if(scc[p[i].fi] != scc[p[i].se])
{
Query(scc[p[i].fi] , scc[p[i].se]);
}
}
ms(visited , 0);
for(int i = 1; i <= tplt ;i++)
{
if(!visited[i]) get(i , -1);
}
for(int i = 1; i <= m ;i++)
{
cout << ans[i];
}
}
/**
**/
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
#define task ""
if(fopen(task".inp","r"))
{
freopen(task".inp","r",stdin);
freopen(task".out","w",stdout);
}
int tc; tc = 1;
while(tc--) solve();
//execute;
}
