#include <iostream>
#include <vector>
#include <cmath>
#include <map>
#include <set>
#include <iomanip>
#include <queue>
#include <algorithm>
#include <numeric>
#include <deque>
#include <complex>
#include <cassert>

using namespace std;
using ll = long long;

int main(){

    int N, K, A, w=('R'^'G'^'B');
    char cc;
    cin >> N >> K;
    vector<char> ans(N+1), c(N+1, 'R');
    for (int i=0; i<K; i++){
        cin >> A >> cc;
        c[A] = cc;
    }

    for (int i=1; i<=N; i++){
        if (i % 3 == 1) ans[i] = c[i];
        else if (i % 3 == 2){
            if (ans[i-1] != c[i]) ans[i] = c[i];
            else{
                if (c[i] == 'R') ans[i] = 'G';
                if (c[i] == 'G') ans[i] = 'B';
                if (c[i] == 'B') ans[i] = 'R';
            }
        }
        else ans[i] = w ^ ans[i-1] ^ ans[i-2];
    }

    for (int i=1; i<=N; i++) cout << ans[i];
    cout << endl;

    return 0;
}