#include <bits/stdc++.h>
#include <random>
using namespace std;
//#include <atcoder/all>
//using namespace atcoder;
using ll = long long;
using vll = vector<ll>;
using vvll = vector<vll>;
using vvvll = vector<vvll>;
using vvvvll = vector<vvvll>;
using vvvvvll = vector<vvvvll>;
using vvvvvvll = vector<vvvvvll>;
using vb = vector<bool>;
using vvb = vector<vb>;
using vvvb = vector<vvb>;
using vvvvb = vector<vvvb>;
using vd = vector<double>;
using vvd = vector<vd>;
using vvvd = vector<vvd>;
using vvvvd = vector<vvvd>;
using vvvvvd = vector<vvvvd>;
#define all(A) A.begin(),A.end()
#define ALL(A) A.begin(),A.end()
#define rep(i, n) for (ll i = 0; i < (ll) (n); i++)
using pqr = priority_queue<pair<ll, ll>, vector<pair<ll, ll>>, greater<pair<ll, ll>>>;

template<class T>
bool chmax(T& p, T q, bool C = 1) {
    if (C == 0 && p == q) {
        return 1;
    }
    if (p < q) {
        p = q;
        return 1;
    }
    else {
        return 0;
    }
}

template<class T>
bool chmin(T& p, T q, bool C = 1) {
    if (C == 0 && p == q) {
        return 1;
    }
    if (p > q) {
        p = q;
        return 1;
    }
    else {
        return 0;
    }
}

ll gcd(ll(a), ll(b)) {
    if (b == 0)return a;
    ll c = a;
    while (a % b != 0) {
        c = a % b;
        a = b;
        b = c;
    }
    return b;
}

ll mod = 1e9 + 7;
ll modPow(long long a, long long n, long long p = mod) {
    if (n == 0) return 1; // 0乗にも対応する場合
    if (n == 1) return a % p;
    if (n % 2 == 1) return (a * modPow(a, n - 1, p)) % p;
    long long t = modPow(a, n / 2, p);
    return (t * t) % p;
}








int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    ll N, K;
    cin >> N >> K;
    string S;
    rep(i, N)S.push_back( 'G');
    rep(k, K) {
        ll A;
        char C;
        cin >> A >> C;
        S[A - 1] = C;
    }
    vll R(3, 0);
    string T = "RGB";
    rep(i, N) {
        ll m = -1;
        ll M = 1e18;
        rep(p, 3)if (chmin(M, R[p]))m = p;
        if (S[i] == 'R') {
            if (R[0] == M) {
                R[0]++;
                cout << 'R';
            }
            else {
                R[m]++;
                cout << T[m];
            }
        }
        if (S[i] == 'G') {
            if (R[1] == M) {
                R[1]++;
                cout << 'G';
            }
            else {
                R[m]++;
                cout << T[m];
            }
        }
        if (S[i] == 'B') {
            if (R[2] == M) {
                R[2]++;
                cout << 'B';
            }
            else {
                R[m]++;
                cout << T[m];
            }
        }
    }
    cout << endl;

}