#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
using ld = long double;
using mint = modint998244353;

int main() {
  int N, M; cin >> N >> M;
  string S; cin >> S;
  string SAC, SWA;
  int cnt = 0;
  for (int i = 0; i < S.size(); i++) {
    if (S[i] == 'A') {
      cnt++;
      if (cnt <= M) SAC += '(';
    }
    if (S[i] == 'C') {
      SAC += ')';
    }
  }
  cnt = 0;
  for (int i = S.size() - 1; i >= 0; i--) {
    if (S[i] == 'A') {
      cnt++;
      if (cnt <= N) SWA += ')';
    }
    if (S[i] == 'W') {
      SWA += '(';
    }
  }
  reverse(SWA.begin(), SWA.end());
  cnt = 0;
  for (int i = 0; i < SAC.size(); i++) {
    if (SAC[i] == '(') cnt++;
    if (SAC[i] == ')') cnt--;
    if (cnt < 0) {
      cout << "No" << endl;
      return 0;
    }
  }
  if (cnt != 0) {
    cout << "No" << endl;
    return 0;
  }
  cnt = 0;
  for (int i = 0; i < SWA.size(); i++) {
    if (SWA[i] == '(') cnt++;
    if (SWA[i] == ')') cnt--;
    if (cnt < 0) {
      cout << "No" << endl;
      return 0;
    }
  }
  if (cnt != 0) {
    cout << "No" << endl;
    return 0;
  }
  cout << "Yes" << endl;
  return 0;
}