#include "gift.h"
#include <bits/stdc++.h>
using namespace std;
vector<tuple<int,int,int>> v;
int A[500005];
int qs[500005];
bool same[500005];
int construct(int n, int r, vector<int> a, vector<int> b, vector<int> x) {
for (int i = 0; i < r; i++) {
a[i]++; b[i]++;
if (x[i] == 1) {
A[a[i]]++;
A[b[i] + 1]--;
}
}
for (int i = 1; i <= n; i++) {
A[i] += A[i - 1];
if (A[i] > 0) {
same[i] = true;
}
}
bool prev = false;
for (int i = 1; i <= n; i++) {
if (prev == 1 && same[i] == 1) {
qs[i] = qs[i - 1];
} else {
qs[i] = (qs[i - 1] + 1) % 2;
}
prev = same[i];
}
for (int i = 1; i <= n; i++) {
qs[i] += qs[i - 1];
}
for (int i = 0; i < r; i++) {
if (x[i] == 1) continue;
if (qs[b[i]] - qs[a[i] - 1] == b[i] - a[i] + 1 || qs[b[i]] - qs[a[i] - 1] == 0) return 0;
}
string S = "";
for (int i = 1; i <= n; i++) {
int d = qs[i] - qs[i - 1];
if (d == 1) S += 'R';
else S += 'B';
}
cout << S << "\n";
craft(S);
return 1;
}
/*static int n, r;
static std::vector<int> a, b, x;
static std::string s;
static int possible = 0;
static int called = 0;
int main() {
assert(scanf("%d %d", &n, &r) == 2);
a.resize(r);
b.resize(r);
x.resize(r);
for (int i = 0; i < r; i++) {
assert(scanf("%d %d %d", &a[i], &b[i], &x[i]) == 3);
}
fclose(stdin);
possible = construct(n, r, a, b, x);
assert(possible == 0 || possible == 1);
printf("%d\n", possible);
if (possible == 1) {
printf("%s\n", s.c_str());
} else {
assert(!called);
}
}*/
