#include<bits/stdc++.h>
using namespace std;
typedef pair<int, int> pii;
void craft(string& s);
int construct(int n, int r, vector<int> a, vector<int> b, vector<int> x){
vector<pii> one, two;
for(int i = 0; i < r; ++i){
if(x[i] == 1) one.push_back({a[i], b[i]});
if(x[i] == 2) two.push_back({a[i], b[i]});
}
sort(one.begin(), one.end());
sort(two.begin(), two.end());
string ans(n, 'R');
int f = 1;
for(auto [l, r] : one){
while(f <= l){
ans[f] = ans[f-1] == 'R'? 'B' : 'R';
++f;
}
while(f <= r){
ans[f] = ans[f-1];
++f;
}
}
while(f < n){
ans[f] = ans[f-1] == 'R'? 'B' : 'R';
++f;
}
// constructed a coloring, lets check if it is valid
vector<int> diff(n, 0);
for(int i = 1; i < n; ++i) diff[i] = diff[i-1] + (ans[i] != ans[i-1]);
for(auto [l, r] : two){
if(diff[l] == diff[r]) return 0;
}
craft(ans);
return 1;
}
