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