#include <bits/stdc++.h>
using namespace std;

using pic = pair<int, char>;


const int N = 1e5 + 10;
int n, k;
pic a[N];

char ans[N];

int cnt[256];

char minc() {
    for(char c : {'R', 'G', 'B'}) {
        bool ok = true;
        for(char v : {'R', 'G', 'B'})
            if(cnt[c] > cnt[v]) {
                ok = false;
                break;
            }
        if(ok) return c;
    }
    return 'r';
}

int main() {
    cin >> n >> k;
    for(int i = 1; i <= k; i ++) {
        cin >> a[i].first >> a[i].second;
    }
    for(int i = 1; i <= n; i ++)
        ans[i] = 'R';
    sort(a + 1, a + k + 1);
    for(int i = 1, cur = 1; i <= k; i ++) {
        auto [x, c] = a[i];
        while(cur < x) ans[cur ++] = minc(), cnt[minc()] ++;
        if(cnt[c] < cnt['R'] || cnt[c] < cnt['G'] || cnt[c] < cnt['B'] || (cnt['R'] == cnt['G'] && cnt['G'] == cnt['B']))
            ans[cur ++] = c, cnt[c] ++;
        else
            ans[cur ++] = minc(), cnt[minc()] ++;
    }

    cout << ans + 1;
}