#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<ll,ll>;
#define fix(x) fixed << setprecision(x)
#define asc(x) x, vector<x>, greater<x>
#define rep(i, n) for(ll i = 0; i < n; i++)
#define all(x) (x).begin(),(x).end()
template<class T>bool chmin(T&a, const T&b){if(a>b){a=b;return 1;}return 0;}
template<class T>bool chmax(T&a, const T&b){if(a<b){a=b;return 1;}return 0;}

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int n,k;
    cin >> n >> k;
    vector<int> check(n,-1);
    rep(i,k){
        int a; char c;
        cin >> a >> c;
        a--;
        if(c=='R') check[a] = 0;
        if(c=='G') check[a] = 1;
        if(c=='B') check[a] = 2;
    }
    string s, t = "RGB";
    vector<bool> ok(3); 
    rep(i,n){
        int x;
        if(!(i%3)) rep(j,3) ok[j] = false;
        if(check[i]>=0 && !ok[check[i]]) x = check[i];
        else{
            rep(j,3) if(!ok[j]) x = j;
        }
        ok[x]= true;
        s += t[x];
    }
    cout << s << '\n';
    return 0;
}