#include <bits/stdc++.h>

using namespace std;
#define rep(i,n) for (int i = 0; i < (int)(n); ++i)
#define rrep(i,n) for (int i = (int)(n-1); i >= 0; --i)
#define Rep(i,a,b) for (int i = a; i < b; ++i)
#define rRep(i,a,b) for (int i = a; i > b; --i)
#define fore(i,a) for(auto &i:a)
#define all(v) (v).begin(),(v).end()
#define rall(v) (v).rbegin(),(v).rend()
#define Unique(v) v.erase(unique(v.begin(), v.end()), v.end());
#define Bit(x,i) (((x)>>(i))&1)
using ll = long long;
using vi = vector<int>;
using vll = vector<long long>;
using vvi = vector<vi>;
using vvll = vector<vll>;
using vb = vector<bool>;
using vs = vector<string>;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
struct settings{settings(){ios_base::sync_with_stdio(0); cin.tie(0); cout<<fixed<<setprecision(15);};}settingss;
const double PI = acos(-1);
const int INF = 1001001001;
const ll LINF = 1001001001001001001LL;

vector<char> C(100100, '.');
char ans[100100];

int main() {
  int N, K; cin >> N >> K;
  rep(i, K) {
    int A; char c; cin >> A >> c;
    C[A-1] = c;
  }
  int i = 0;
  while(i < N) {
    string tmp = "RGB";
    do {
      if(C[i] != '.') {
        if(tmp[0] != C[i]) continue;
      }
      if(C[i+1] != '.') {
        if(tmp[0] != C[i+1] && tmp[1] != C[i+1]) continue;
      }
      break;
    } while(next_permutation(all(tmp)));
    ans[i] = tmp[0];
    ans[i+1] = tmp[1];
    ans[i+2] = tmp[2];
    i += 3;
  }
  rep(i, N) cout << ans[i];
  cout << endl;
}