// #define _GLIBCXX_DEBUG // for STL debug (optional)
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <string>
#include <cstring>
#include <deque>
#include <list>
#include <queue>
#include <stack>
#include <vector>
#include <utility>
#include <algorithm>
#include <map>
#include <set>
#include <complex>
#include <cmath>
#include <limits>
#include <cfloat>
#include <climits>
#include <ctime>
#include <cassert>
#include <numeric>
#include <fstream>
#include <functional>
#include <bitset>
using namespace std;
using ll = long long int;
using int64 = long long int;
 
template<typename T> void chmax(T &a, T b) {a = max(a, b);}
template<typename T> void chmin(T &a, T b) {a = min(a, b);}
template<typename T> void chadd(T &a, T b) {a = a + b;}
 
int dx[] = {0, 0, 1, -1};
int dy[] = {1, -1, 0, 0};
const int INF = 1LL << 29;
const ll LONGINF = 1LL << 60;
const ll MOD = 1000000007LL;
 
int main() {
    ll S, P; cin >> S >> P;

    // N = S - M
    // (S - M) * M = P
    // SM - M^2 = P
    // M^2 - SM + P = 0
    ll ans = 0;
    for(ll M=1; M<=8000000; M++) {
        ll N = S - M;
        if(N <= 0) break;
        if(N*M == P) ans++;
    }
    cout << (ans > 0 ? "Yes" : "No") << endl;
    return 0;
}

#include <bits/stdc++.h>
using namespace std;

#ifdef _DEBUG
#include "_DEBUG.hpp"
#endif
#define int long long
const long long inf = 2e18;
const int mod = 1e9 + 7;

template <typename T>
istream &operator>>(istream &is, vector<T> &v) {
  for (T &in : v) is >> in;
  return is;
}

template <class T>
vector<T> make_vec(size_t a) {
  return vector<T>(a);
}

template <class T, class... Ts>
auto make_vec(size_t a, Ts... ts) {
  return vector<decltype(make_vec<T>(ts...))>(a, make_vec<T>(ts...));
}

template <class T, class V>
typename enable_if<is_class<T>::value == 0>::type fill(T &t, const V &v) {
  t = v;
}

template <class T, class V>
typename enable_if<is_class<T>::value != 0>::type fill(T &t, const V &v) {
  for (auto &e : t) fill(e, v);
}

// nCr mod p (p < 10) O(100 + log(n))
int Lucas(int n, int r, int p) {
  assert(n >= r);
  vector<vector<int>> dp(p, vector<int>(p));  // dp[n][r] = nCr
  for (int i = 0; i < p; i++) {
    dp[i][0] = 1;
    for (int j = 1; j <= i; j++) {
      dp[i][j] = (dp[i - 1][j - 1] + dp[i - 1][j]) % p;
    }
  }
  int res = 1;
  while (n > 0) {
    res = (res * dp[n % p][r % p]) % p;
    n /= p;
    r /= p;
  }
  return res;
}

signed main() {
  int n;
  cin >> n;
  string s;
  cin >> s;

  int ans = 0;
  for (int i = 0; i < n; i++) {
    int color = (s[i] == 'B' ? 0 : s[i] == 'W' ? 1 : 2);
    ans = (ans + Lucas(n - 1, i, 3) * color) % 3;
  }
  if (n % 2 == 0) ans = (3 - ans) % 3;
  cout << (ans == 0 ? 'B' : ans == 1 ? 'W' : 'R') << endl;

  return 0;
}