#include <bits/stdc++.h>
using namespace std;
int main() {
    int N, K, M = 100002;
    cin >> N >> K;
    vector<int> A(K);
    vector<char> c(K), ans(M, 'A');
    vector<string> str = {"BGR", "BRG", "GBR", "GRB", "RBG", "RGB"};
    for( int i = 0; i < K; i++ ) {
        cin >> A[i] >> c[i];
        ans[--A[i]] = c[i];
    }
    for( int i = 0; i < M; i+=3 ) {
        string str2 = "AAA";
        for( int j = 0; j < 3; j++ ) {
            for( int k = 0; k < 3; k++ ) {
                if( str2[k] == ans[i+j] ) break;
                if( str2[k] != 'A' ) continue;
                if( str2[k] == 'A' ) {
                    str2[k] = ans[i+j];
                    break;
                }
            }
        }
        // cout << str2 << endl;
        // cout << *lower_bound(str.begin(), str.end(), str2) << endl;
        str2 = *lower_bound(str.begin(), str.end(), str2);
        for( int j = 0; j < 3; j++ ) {
            ans[i+j] = str2[j];
        }
    }
    for( int i = 0; i < N; i++ ) {
        cout << ans[i];
    }
    cout << endl;
}