#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  int N;
  cin >> s;
  cin >> N;
  int rc, bc;
  for (int i = 0; i < N; i++) {
    if (s[i] == 'R')
      rc++;
    else
      bc++;
  }
  if (rc > bc)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
}
