using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static int[][] NArr(int n) => Enumerable.Repeat(0, n).Select(_ => NList).ToArray();
    static void Main()
    {
        var c = NList;
        var (n, k) = (c[0], c[1]);
        var list = new char[n];
        for (var _ = 0; _ < k; ++_)
        {
            var s = ReadLine().Split();
            list[int.Parse(s[0]) - 1] = s[1][0];
        }
        var res = new char[n];
        var x = new string[] { "RGB", "RBG", "GBR", "GRB", "BRG", "BGR" };
        for (var i = 0; i < n; i += 3)
        {
            var info = list.Skip(i).Take(3).ToList();
            foreach (var xi in x)
            {
                if (Fit(info, xi))
                {
                    for (var j = 0; j < info.Count; ++j)
                    {
                        res[i + j] = xi[j];
                    }
                    break;
                }
            }
        }
        WriteLine(res);
    }
    static bool Fit(List<char> info, string x)
    {
        var r = false;
        var g = false;
        var b = false;
        if (info[0] == 'R')
        {
            if (x[0] != 'R') return false;
            r = true;
        }
        else if (info[0] == 'G')
        {
            if (x[0] != 'G') return false;
            g = true;
        }
        else if (info[0] == 'B')
        {
            if (x[0] != 'B') return false;
            b = true;
        }
        if (info.Count == 1) return true;
        if (info[1] == 'R')
        {
            if (!r && x[1] != 'R') return false;
            r = true;
        }
        else if (info[1] == 'G')
        {
            if (!g && x[1] != 'G') return false;
            g = true;
        }
        else if (info[1] == 'B')
        {
            if (!b && x[1] != 'B') return false;
            b = true;
        }
        if (info.Count == 2) return true;
        if (info[2] == 'R')
        {
            if (!r && x[2] != 'R') return false;
        }
        else if (info[2] == 'G')
        {
            if (!g && x[2] != 'G') return false;
        }
        else if (info[2] == 'B')
        {
            if (!b && x[2] != 'B') return false;
        }
        return true;
    }
}