#include <bits/stdc++.h>

using namespace std;

const int N = 400010;
char s[N];

int wa[N];
int ac[N];

int main()
{
    int n, m;
    scanf("%d%d", &n, &m);
    scanf("%s", s);
    int all = n + n + m + m;
    int t = m;

    int wi = 0, ai = 0;
    for (int i = 0; i < all; i++)
    {
        char c = s[i];
        if (c == 'W')
            wa[wi++] = 1;
        else if (c == 'C')
            ac[ai++] = -1;
        else if (t == 0)
            wa[wi++] = -1;
        else
        {
            ac[ai++] = 1;
            t--;
        }
    }

    bool ok = true;

    int* end = ac + m * 2;
    int* p = ac;
    int sum = 0;
    for (; p != end; p++)
    {
        sum += *p;
        ok &= sum >= 0;
    }
    end = wa + n * 2;
    p = wa;
    sum = 0;
    for (; p != end; p++)
    {
        sum += *p;
        ok &= sum >= 0;
    }

    if (ok)
        printf("Yes\n");
    else
        printf("No\n");

    return 0;
}