#include <bits/stdc++.h>
#define mp make_pair
#define pb push_back
#define X first
#define Y second
#define y0 y12
#define y1 y22
#define INF 987654321
#define PI 3.141592653589793238462643383279502884
#define fup(i,a,b,c) for(int (i)=(a);(i)<=(b);(i)+=(c))
#define fdn(i,a,b,c) for(int (i)=(a);(i)>=(b);(i)-=(c))
#define MEM0(a) memset((a),0,sizeof(a))
#define MEM_1(a) memset((a),-1,sizeof(a))
#define ALL(a) a.begin(),a.end()
#define SYNC ios_base::sync_with_stdio(false);cin.tie(0)
using namespace std;
typedef long long ll;
typedef long double ld;
typedef double db;
typedef unsigned int uint;
typedef unsigned long long ull;
typedef pair<int, int> Pi;
typedef pair<ll, ll> Pll;
typedef pair<ld, ld> Pd;
typedef vector<int> Vi;
typedef vector<ll> Vll;
typedef vector<db> Vd;
typedef vector<Pi> VPi;
typedef vector<Pll> VPll;
typedef vector<Pd> VPd;
typedef tuple<int, int, int> iii;
typedef tuple<int, int, int, int> iiii;
typedef tuple<ll, ll, ll> LLL;
typedef vector<iii> Viii;
typedef vector<LLL> VLLL;
typedef complex<double> base;
const int MOD = 1000000007;
ll POW(ll a, ll b, ll MMM = MOD) { ll ret = 1; for (; b; b >>= 1, a = (a*a) % MMM)if (b & 1)ret = (ret*a) % MMM; return ret; }
int dx[] = { 0,1,0,-1,1,1,-1,-1 }, dy[] = { 1,0,-1,0,1,-1,1,-1 };
int ddx[] = { -1,-2,1,-2,2,-1,2,1 }, ddy[] = { -2,-1,-2,1,-1,2,1,2 };
#include "gift.h"
int parent[500000];
int find(int a)
{
if (parent[a] < 0)return a;
return parent[a] = find(parent[a]);
}
void merge(int a, int b)
{
a = find(a), b = find(b);
if (a != b)
{
parent[a] = b;
}
}
int construct(int n, int r, Vi a, Vi b, Vi x){
MEM_1(parent);
fup(i,0,r-1,1){
if(x[i]==2)continue;
int x=find(a[i]),y=find(b[i]);
while(x!=y){
merge(x,x+1);
x=find(x);
}
}
fup(i,0,r-1,1){
if(x[i]==2){
if(find(a[i])==find(b[i]))return 0;
}
}
string s;
int t=0;
fup(i,0,n-1,1){
s+=t?'B':'R';
if(parent[i]<0)t^=1;
}
craft(s);
return 1;
}
/*
int main() {
}*/
