#include <stdio.h>
#include <atcoder/all>
#include <bits/stdc++.h>
using namespace std;
using namespace atcoder;
using mint = modint998244353;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf32 1000000001
#define Inf64 4000000000000000001


int main(){
	
	int N,M;
	cin>>N>>M;
	
	string s;
	cin>>s;
	vector<int> x,y,z;
	rep(i,s.size()){
		if(s[i]=='W')x.push_back(i);
		if(s[i]=='A')y.push_back(i);
		if(s[i]=='C')z.push_back(i);
	}
	
	rep(i,y.size()){
		if(i<M){
			if(y[i]>=z[i]){
				cout<<"No"<<endl;
				return 0;
			}
		}
		else{
			if(y[i]<=x[i-M]){
				cout<<"No"<<endl;
				return 0;
			}
		}
	}
	cout<<"Yes"<<endl;
	
	return 0;
}