#include <algorithm>
#include <bitset>
#include <cassert>
#include <cmath>
#include <cstdio>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <unordered_set>
using namespace std;
#if __has_include(<atcoder/all>)
#include <atcoder/all>
using namespace atcoder;
#endif
#define GET_MACRO(_1, _2, _3, NAME, ...) NAME
#define _rep(i, n) _rep2(i, 0, n)
#define _rep2(i, a, b) for(int i = (int)(a); i < (int)(b); i++)
#define rep(...) GET_MACRO(__VA_ARGS__, _rep2, _rep)(__VA_ARGS__)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
using i64 = long long;
template<class T, class U>
bool chmin(T& a, const U& b) { return (b < a) ? (a = b, true) : false; }
template<class T, class U>
bool chmax(T& a, const U& b) { return (b > a) ? (a = b, true) : false; }
inline void YesNo(bool f) { std::cout << (f? "Yes": "No") << std::endl; }

template<typename T>istream& operator>>(istream&i,vector<T>&v){rep(j,v.size())i>>v[j];return i;}
template<typename T>string join(vector<T>&v){stringstream s;rep(i,v.size())s<<' '<<v[i];return s.str().substr(1);}
template<typename T>ostream& operator<<(ostream&o,vector<T>&v){if(v.size())o<<join(v);return o;}
template<typename T>string join(vector<vector<T>>&vv){string s="\n";rep(i,vv.size())s+=join(vv[i])+"\n";return s;}
template<typename T>ostream& operator<<(ostream&o,vector<vector<T>>&vv){if(vv.size())o<<join(vv);return o;}

int num(char c){
    return c == 'R'? 0: c == 'G'? 1: 2;
}

int main(){
    int n, k;
    cin >> n >> k;
    string t = "RGB";
    vector<vector<pair<int, int>>> p(n / 3);
    string ans;
    rep(i, n) ans += 'A';
    rep(i, k){
        int a;
        char c;
        cin >> a >> c;
        if (a % 3 == 0) continue;
        a--;
        if (a % 3 == 0) ans[a] = c;
        else{
            if (ans[a - 1] == c) continue;
            else ans[a] = c;
        }
    }
    for (int i = 0; i < n; i += 3){
        set<char> s = {'R', 'G', 'B'};
        rep(j, i, min(n, i + 3)){
            s.erase(ans[j]);
        }
        rep(j, i, min(n, i + 3)){
            if (ans[j] == 'A'){
                ans[j] = *s.begin();
                s.erase(s.begin());
            }
        }
    }
    cout << ans <<  endl;
}