#include <algorithm>
#include <iostream>
using namespace std;
typedef pair<int, char> P;

int main()
{
    int n, k;
    cin >> n >> k;
    P p[200005];
    for (int i = 0; i < k; i++)
    {
        cin >> p[i].first >> p[i].second;
    }
    sort(p, p + k);
    p[k] = P(n, 'R');
    p[k + 1] = P(n, 'G');
    p[k + 2] = P(n, 'B');
    int d[3]{0};
    string ans;
    for (int i = 0; i < k + 3; i++)
    {
        while (d[(int)p[i].second % 3] < (p[i].first + 2) / 3)
        {
            ans += p[i].second;
            d[(int)p[i].second % 3]++;
        }
    }
    cout << ans.substr(0, n) << endl;
}