import java.io.*;
import java.util.*;

class Main
{
    public static void main(String args[])throws Exception
    {
        BufferedReader bu=new BufferedReader(new InputStreamReader(System.in));
        StringBuilder sb=new StringBuilder();
        String s[]=bu.readLine().split(" ");
        int n=Integer.parseInt(s[0]),k=Integer.parseInt(s[1]);

        int i;
        char ans[]=new char[n],q[]=new char[n];
        Arrays.fill(ans,' '); Arrays.fill(q,' ');
        for(i=0;i<k;i++)
        {
            s=bu.readLine().split(" ");
            int in=Integer.parseInt(s[0])-1;
            q[in]=s[1].charAt(0);
        }

        String ways[]={"RGB","RBG","BRG","BGR","GRB","GBR"};
        for(i=0;i<n;i+=3)
        for(String x:ways)
        {
            int j;
            for(j=0;j<3;j++)
            if(i+j<n) ans[i+j]=x.charAt(j);

            int c[]=new int[3];
            boolean ok=true;
            for(j=0;j<3;j++)
            if(i+j<n)
            {
                if(ans[i+j]=='R') c[0]++;
                else if(ans[i+j]=='B') c[1]++;
                else c[2]++;

                int max=Math.max(Math.max(c[0],c[1]),c[2]);
                if(q[i+j]!=' ')
                {
                    int here=2;
                    if(q[i+j]=='R') here=0;
                    else if(q[i+j]=='B') here=1;
                    if(c[here]!=max) {ok=false; break;}
                }
            }
            if(ok) break;
        }
        System.out.println(new String(ans));
    }
}