#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
using ll = long long;
constexpr int INF = 0x3f3f3f3f;
constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL;
constexpr double EPS = 1e-8;
constexpr int MOD = 998244353;
// constexpr int MOD = 1000000007;
constexpr int DY4[]{1, 0, -1, 0}, DX4[]{0, -1, 0, 1};
constexpr int DY8[]{1, 1, 0, -1, -1, -1, 0, 1};
constexpr int DX8[]{0, -1, -1, -1, 0, 1, 1, 1};
template <typename T, typename U>
inline bool chmax(T& a, U b) { return a < b ? (a = b, true) : false; }
template <typename T, typename U>
inline bool chmin(T& a, U b) { return a > b ? (a = b, true) : false; }
struct IOSetup {
  IOSetup() {
    std::cin.tie(nullptr);
    std::ios_base::sync_with_stdio(false);
    std::cout << fixed << setprecision(20);
  }
} iosetup;

int main() {
  constexpr int C = 3;
  const char colors[C]{'R', 'G', 'B'};
  int n, k; cin >> n >> k;
  vector<char> c(n, '*');
  while (k--) {
    int a; cin >> a; --a;
    cin >> c[a];
  }
  string ans(n, '?');
  for (int i = 0; i < n; i += C) {
    vector<char> cs;
    for (int j = 0; j < C && i + j < n; ++j) {
      if (c[i + j] != '*' && count(ALL(cs), c[i + j]) == 0) cs.emplace_back(c[i + j]);
    }
    REP(j, C) {
      if (count(ALL(cs), colors[j]) == 0) cs.emplace_back(colors[j]);
    }
    for (int j = 0; j < C && i + j < n; ++j) {
      ans[i + j] = cs[j];
    }
  }
  cout << ans << '\n';
  return 0;
}