#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  int n, m;
  string s;
  cin >> n >> m >> s;
  vector<int> a;
  rep(i, s.size()) if (s[i] == 'A') a.push_back(i);
  bool ok = true;
  rep(i, s.size()) {
    if (s[i] == 'W') {
      assert(!a.empty());
      int j = a.back();
      if (j < i) ok = false;
      a.pop_back();
    }
  }
  for (int i = s.size() - 1; i >= 0; --i) {
    if (s[i] == 'C') {
      assert(!a.empty());
      int j = a.back();
      if (j > i) ok = false;
      a.pop_back();
    }
  }
  assert(a.empty());
  cout << (ok ? "Yes" : "No") << '\n';
  return 0;
}