#include <bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
using ll = long long;
using vi = vector<int>;
using vvi = vector<vector<int>>;
using pii = pair<int, int>;
#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
#define repr(i, n) for (int i = (int)(n - 1); i >= 0; --i)

int main() {
    const string str = "BRG";
    int n, K;
    cin >> n >> K;
    vector<pii> p(K);
    rep(i, K) {
        int k;
        char c;
        cin >> k >> c, k--;
        p[i] = pii(k, (int)c % 3);
    }
    sort(p.begin(), p.end());

    string ret = "";
    vector<bool> mx(3, false);
    for (int i = 0, k = 0; i < n; i++) {
        if (i % 3 == 0) {
            rep(j, 3) mx[j] = false;
        }
        if (k < K && p[k].first == i) {
            int c = p[k].second;
            if (!mx[c]) {
                mx[c] = true;
                ret += str[c];
            } else {
                rep(j, 3) {
                    if (!mx[j]) {
                        mx[j] = true;
                        ret += str[j];
                        break;
                    }
                }
            }
            k++;
        } else {
            rep(j, 3) {
                if (!mx[j]) {
                    mx[j] = true;
                    ret += str[j];
                    break;
                }
            }
        }
    }
    cout << ret << endl;
    return 0;
}