#include<iostream>
using namespace std;
int N,K;
char A[1<<17];
int main()
{
	cin>>N>>K;
	for(int i=1;i<=N;i++)A[i]='R';
	for(int i=0;i<K;i++)
	{
		int a;cin>>a;
		cin>>A[a];
	}
	string ans="";
	for(int i=1;i<=N;i+=3)
	{
		ans+=A[i];
		if(i+2<=N)
		{
			if(A[i]==A[i+1])
			{
				if(A[i]==A[i+2])
				{
					if(A[i]=='R')ans+="GB";
					else if(A[i]=='G')ans+="RB";
					else ans+="RG";
				}
				else
				{
					ans+=A[i+2];
					ans+='R'^'G'^'B'^A[i]^A[i+2];
				}
			}
			else
			{
				ans+=A[i+1];
				ans+='R'^'G'^'B'^A[i]^A[i+1];
			}
		}
		else if(i+1<=N)
		{
			ans+=A[i+1];
		}
	}
	cout<<ans<<endl;
}