#include <bits/extc++.h>
#define rep(i, n) for (int i = 0; i < (n); ++i)

using std::cin;
using std::cout;
using std::string;

int main() {
    int n, k;
    cin >> n >> k;
    
    string s(n, 'R');
    rep(i, k) {
        int p; char c;
        cin >> p >> c;
        --p;
        s[p] = c;
    }
    
    rep(i, n) {
        if (i%3 == 1) {
            if (s[i] == s[i-1]) {
                if (s[i-1] == 'R') s[i] = 'G';
                else s[i] = 'R';
            }
        }
        if (i%3 == 2) {
            s[i] = 'R' ^ 'G' ^ 'B' ^ s[i-1] ^ s[i-2];
        }
    }
    
    cout << s << '\n'; 
    
    return 0;
}