#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <atcoder/modint>
using namespace std;
using i32 = int;
using u32 = unsigned int;
using i64 = long long;
using u64 = unsigned long long;
#define rep(i,n) for(int i=0; i<(int)(n); i++)
const i64 INF = 1001001001001001001;

using Modint = atcoder::static_modint<998244353>;

int main(){
    int N, M; cin >> N >> M;
    string S; cin >> S;
    vector<int> pW, pA, pC;
    rep(i,S.size()){
        char c = S[i];
        if(c == 'W') pW.push_back(i);
        if(c == 'A') pA.push_back(i);
        if(c == 'C') pC.push_back(i);
    }
    bool ans = true;
    rep(i,N) if(pW[i] >= pA[M+i]) ans = false;
    rep(i,M) if(pA[i] >= pC[i]) ans = false;
    cout << (ans ? "Yes\n" : "No\n");
    return 0;
}



struct ios_do_not_sync{
    ios_do_not_sync(){
        ios::sync_with_stdio(false);
        cin.tie(nullptr);
    }
} ios_do_not_sync_instance;