#include <iostream>

using namespace std;
int main(){
  int n,m;cin>>n>>m;
  string s;cin>>s;
  int nww = 0, nwa = 0;
  int nwwi = -1;
  int nwai = s.size();
  for(int i = 0; s.size() > i; i++){
    if(s[i] == 'W'){
      nww++;
      if(nww == n){
        nwwi = i;
      }
    }
  }
  for(int i = s.size()-1; 0 <= i; i--){
    if(s[i] == 'A'){
      nwa++;
      if(nwa == n){
        nwai = i;
      }
    }
  }
  if(n && nwwi > nwai){
    cout << "No" << endl;
    return 0;
  }
  nwa = 0;
  bool ok = false;
  int nw = 0;
  int nwv = 0;
  for(int i = 0; s.size() > i; i++){
    if(s[i] == 'A' && nwai > i){
      nw++;
    }else if(s[i] == 'C'){
      nw--;
      if(nw >= 0)nwv++;
    }
  }
  if(nwv >= m){
    cout << "Yes" << endl;
  }else{
    cout << "No" << endl;
  }
}