#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pll = pair<ll, ll>;
#define drep(i, cc, n) for (ll i = (cc); i <= (n); ++i)
#define rep(i, n) drep(i, 0, n - 1)
#define all(a) (a).begin(), (a).end()
#define pb push_back
#define fi first
#define se second

const ll MOD = 1000000007;
const ll MOD2 = 998244353;
const ll INF = 1LL << 60;
const ll MAX_N = 2e5;

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    ll n, m; cin >> n >> m;
    string s; cin >> s;

    set<ll> a, w, c;
    rep(i, (ll)s.size()){
        if(s[i]=='A'){
            a.insert(i);
        }else if(s[i]=='W'){
            w.insert(-i);
        }else{
            c.insert(i);
        }
    }

    for(auto itr=w.begin(); itr!=w.end(); itr++){
        ll idx = -*itr;
        auto itr2 = a.end();
        itr2--;
        if(idx < *itr2){
            a.erase(itr2);
        }else{
            cout << "No" << endl;
            return 0;
        }
    }

    for(auto itr=c.begin(); itr!=c.end(); itr++){
        ll idx = *itr;
        if(*a.begin() < idx){
            a.erase(a.begin());
        }else{
            cout << "No" << endl;
            return 0;
        }
    }

    cout << "Yes" << endl;
}