#include <bits/stdc++.h>
#define FOR(i,l,r) for(int i=(l); i<=(r); ++i)
#define REP(i,l,r) for(int i=(l); i<(r); ++i)
#define FORD(i,r,l) for(int i=(r); i>=(l); --i)
#define REPD(i,r,l) for(int i=(r)-1; i>=(l); --i)
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template<class key, class value = null_type, class cmp = std::less<key>>
using ordered_set = tree<key, value, cmp, rb_tree_tag, tree_order_statistics_node_update>;
void craft(std::string &s);
int construct(int n, int r, vector<int> a, vector<int> b, vector<int> x) {
ordered_set<int> ST;
FOR(i, 0, n) ST.insert(i);
REP(i, 0, r) if (x[i] == 1) {
while (true) {
auto pos = ST.upper_bound(a[i]);
if (*pos <= b[i]) ST.erase(pos);
else break;
}
}
REP(i, 0, r) if (x[i] == 2) {
if (ST.upper_bound(a[i]) == ST.upper_bound(b[i]))
return 0;
}
string s;
int tmp = 0;
for(auto i2 = ST.begin(), i = i2++; i2 != ST.end(); i = i2++) {
tmp ^= 1;
char c = tmp ? 'R' : 'B';
REP(j, *i, *i2) s += c;
}
craft(s);
return 1;
}
