#include <iostream>
#include <string>
using namespace std;

bool check(string s, char a, char b) {
    int na = 0;
    for (auto c : s) {
        if (c == a)
            ++na;
        else
            --na;
        if (na < 0) return false;
    }
    return true;
}

int main() {
    int N, M;
    string S;
    cin >> N >> M >> S;
    string wa, ac;
    int naac = 0;
    for (auto c : S) {
        if (c == 'W') {
            wa += c;
        } else if (c == 'C') {
            ac += c;
        } else {
            if (naac < M) {
                ac += c;
                ++naac;
            } else {
                wa += c;
            }
        }
    }

    if (check(ac, 'A', 'C') and check(wa, 'W', 'A')) {
        puts("Yes");
    } else {
        puts("No");
    }
}