using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;

class Program
{
    #region library
    static int n = 0;
    static int r = 0;
    static int c = 0;
    static string s = "";
    static long sum = 0;
    static long cnt = 0;
    static long max = long.MinValue;
    static long min = long.MaxValue;
    static long inf = long.MaxValue / 2;
    static bool flg = false;
    static long[] arr;
    static char[,] map;
    static long[,] imap;
    static string alpha = "abcdefghijklmnopqrstuvwxyz";
    static int mod = 1000000007;

    public class Input { static readonly char[] separator = { ' ', '\r', '\n' }; readonly StreamReader sr; readonly Queue<string> queue; public Input(string path = "") { queue = new Queue<string>(); if (string.IsNullOrEmpty(path)) { sr = new StreamReader(Console.OpenStandardInput()); } else { sr = new StreamReader(path); } } public void SetText(IEnumerable<string> items) { foreach (var item in items) { SetText(item); } } public bool SetText(string s) { if (s == null) return false; foreach (var elem in s.Trim().Split(separator, StringSplitOptions.RemoveEmptyEntries)) { queue.Enqueue(elem); } return true; } public bool Any() { return queue.Any() || Read(); } bool Read() { if (!SetText(sr.ReadLine())) return false; if (!queue.Any()) return Read(); return queue.Any(); } public string Next() { if (!queue.Any() && !Read()) { return ""; } return queue.Dequeue(); } bool Accumulate(int n) { while (queue.Count() < n) { if (!Read()) return false; } return true; } public int NextInt() { return int.Parse(Next()); } public long NextLong() { return long.Parse(Next()); } public double NextDouble() { return double.Parse(Next()); } T[] NextT<T>(int n, T offset, Func<string, T> parse, Func<T, T, T> add) { if (!Accumulate(n)) return null; var a = new T[n]; for (int i = 0; i < n; i++) a[i] = add(parse(queue.Dequeue()), offset); return a; } public string[] Next(int n) { return NextT(n, "", x => x, (x, y) => x); } public int[] NextInt(int n, int offset = 0) { return NextT(n, offset, int.Parse, (x, y) => x + y); } public long[] NextLong(int n, long offset = 0) { return NextT(n, offset, long.Parse, (x, y) => x + y); } public double[] NextDouble(int n, double offset = 0.0) { return NextT(n, offset, double.Parse, (x, y) => x + y); } }
    static Input input;
    static int Int() { return input.NextInt(); }
    static long Long() { return input.NextLong(); }
    static double Double() { return input.NextDouble(); }
    static string Text() { return input.Next(); }
    static void wl(object obj = null) { Console.WriteLine(obj); }
    static void w(object obj) { Console.Write(obj); }
    static void YES() { wl("YES"); }
    static void NO() { wl("NO"); }
    static void YN(bool b) { if (b) YES(); else NO(); }
    static void Yes() { wl("Yes"); }
    static void No() { wl("No"); }
    static void yn(bool b) { if (b) Yes(); else No(); }
    static void Sum() { wl(sum); }
    static void Cnt() { wl(cnt); }
    static void Max() { wl(max); }
    static void Min() { wl(min); }
    static void swap<T>(ref T a, ref T b) { var w = a; a = b; b = w; }
    static void SetArray(long[] array = null) { if (array != null) { for (int i = 0; i < array.Length; i++) { array[i] = Long(); } } else { if (n == 0) { n = Int(); } arr = new long[n]; for (int i = 0; i < n; i++) { arr[i] = Long(); } } }
    static void ShowArray(long[] array = null) { if (array != null) { wl(string.Join(" ", array)); } else if (arr != null) { wl(string.Join(" ", arr)); } }
    static void CompressArray() { var list = arr.ToList(); list = list.OrderBy(x => x).ToList(); var dic = new Dictionary<long, long>(); var cnt = 0; for (int i = 0; i < list.Count; i++) { if (!dic.ContainsKey(list[i])) { dic.Add(list[i], cnt); cnt++; } } var arr2 = new long[arr.Length]; for (int i = 0; i < arr.Length; i++) { arr2[i] = dic[arr[i]]; } arr = arr2; }
    static void SetMap(char[,] map2 = null) { if (r == 0 && c == 0) { r = Int(); c = Int(); } if (map2 != null) { for (int i = 0; i < r; i++) { s = Text(); for (int j = 0; j < c; j++) { map2[i, j] = s[j]; } } } else { map = new char[r, c]; for (int i = 0; i < r; i++) { s = Text(); for (int j = 0; j < c; j++) { map[i, j] = s[j]; } } } }
    static void RotateMap() { var map2 = new char[c, r]; for (int i = 0; i < r; i++) { for (int j = 0; j < c; j++) { map2[j, r - i - 1] = map[i, j]; } } map = map2; }
    static void SetIMap(long[,] imap2 = null) { if (r == 0 && c == 0) { r = Int(); c = Int(); } if (imap2 != null) { for (int i = 0; i < r; i++) { for (int j = 0; j < c; j++) { imap2[i, j] = Long(); } } } else { imap = new long[r, c]; for (int i = 0; i < r; i++) { for (int j = 0; j < c; j++) { imap[i, j] = Long(); } } } }
    static void ShowMap(char[,] map2 = null) { for (int i = 0; i < r; i++) { for (int j = 0; j < c; j++) { if (map2 != null) w(map2[i, j] + " "); else w(map[i, j] + " "); } wl(); } }
    static void ShowIMap(long[,] imap2 = null) { for (int i = 0; i < r; i++) { for (int j = 0; j < c; j++) { if (imap2 != null) w(imap2[i, j] + " "); else w(imap[i, j] + " "); } wl(); } }
    #endregion

    #region main
    static void Main(string[] args) { var sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false }; Console.SetOut(sw); input = new Input(); try { Solve(); } catch (Exception ex) { wl(ex); if (!(args.Length >= 1 && args[0] == "/debug")) throw ex; } Console.Out.Flush(); }
    public static void Solve()
    {
        n = Int();
        var m = Int();
        s = Text();

        var mw = new MultiSet<int>();
        var ma = new MultiSet<int>();
        var mc = new MultiSet<int>();
        for (int i = 0; i < s.Length; i++)
        {
            if (s[i] == 'W') mw.Add(i);
            if (s[i] == 'A') ma.Add(i);
            if (s[i] == 'C') mc.Add(i);
        }

        flg = true;
        while (mw.Count() > 0 || ma.Count() > 0 || mc.Count() > 0)
        {
            if (mc.Count() > 0)
            {
                if (mc[0] > ma[0])
                {
                    mc.Remove(mc[0]);
                    ma.Remove(ma[0]);
                }
                else
                {
                    flg = false;
                }
            }
            else
            {
                if (mw[0] < ma[0])
                {
                    mw.Remove(mw[0]);
                    ma.Remove(ma[0]);
                }
                else
                {
                    flg = false;
                }
            }

            if (!flg) break;
        }

        yn(flg);
    }
    #endregion


    #region multiset 
    //SortedListの高速版・追加時は自動で昇順ソート・UpperBound・LowerBoundnによる検索・削除も可能
    public class MultiSet<T> : Set<T> where T : IComparable
    {
        public override void Add(T v)
        {
            if (_root == null) _root = new SB_BinarySearchTree<T>.Node(v);
            else _root = SB_BinarySearchTree<T>.Insert(_root, v);
        }
    }
    public class Set<T> where T : IComparable
    {
        protected SB_BinarySearchTree<T>.Node _root;

        public T this[int idx] { get { return ElementAt(idx); } }

        public long Count()
        {
            return SB_BinarySearchTree<T>.Count(_root);
        }

        public virtual void Add(T v)
        {
            if (_root == null) _root = new SB_BinarySearchTree<T>.Node(v);
            else
            {
                if (SB_BinarySearchTree<T>.Find(_root, v) != null) return;
                _root = SB_BinarySearchTree<T>.Insert(_root, v);
            }
        }

        public void Clear()
        {
            _root = null;
        }

        public void Remove(T v)
        {
            _root = SB_BinarySearchTree<T>.Remove(_root, v);
        }

        public bool Contains(T v)
        {
            return SB_BinarySearchTree<T>.Contains(_root, v);
        }

        public T ElementAt(long k)
        {
            var node = SB_BinarySearchTree<T>.FindByIndex(_root, k);
            if (node == null) throw new IndexOutOfRangeException();
            return node.Value;
        }

        public long Count(T v)
        {
            return SB_BinarySearchTree<T>.UpperBound(_root, v) - SB_BinarySearchTree<T>.LowerBound(_root, v);
        }

        public long LowerBound(T v)
        {
            return SB_BinarySearchTree<T>.LowerBound(_root, v);
        }

        public long UpperBound(T v)
        {
            return SB_BinarySearchTree<T>.UpperBound(_root, v);
        }

        public Tuple<long, long> EqualRange(T v)
        {
            if (!Contains(v)) return new Tuple<long, long>(-1, -1);
            return new Tuple<long, long>(SB_BinarySearchTree<T>.LowerBound(_root, v), SB_BinarySearchTree<T>.UpperBound(_root, v) - 1);
        }

        public List<T> ToList()
        {
            return new List<T>(SB_BinarySearchTree<T>.Enumerate(_root));
        }
    }

    public class SB_BinarySearchTree<T> where T : IComparable
    {
        public class Node
        {
            public T Value;
            public Node LChild;
            public Node RChild;
            public long Count;     //size of the sub tree

            public Node(T v)
            {
                Value = v;
                Count = 1;
            }
        }

        static Random _rnd = new Random();

        public static long Count(Node t)
        {
            return t == null ? 0 : t.Count;
        }

        static Node Update(Node t)
        {
            t.Count = Count(t.LChild) + Count(t.RChild) + 1;
            return t;
        }

        public static Node Merge(Node l, Node r)
        {
            if (l == null || r == null) return l == null ? r : l;

            if ((double)Count(l) / (double)(Count(l) + Count(r)) > _rnd.NextDouble())
            {
                l.RChild = Merge(l.RChild, r);
                return Update(l);
            }
            else
            {
                r.LChild = Merge(l, r.LChild);
                return Update(r);
            }
        }

        /// <summary>
        /// split as [0, k), [k, n)
        /// </summary>
        public static Tuple<Node, Node> Split(Node t, long k)
        {
            if (t == null) return new Tuple<Node, Node>(null, null);
            if (k <= Count(t.LChild))
            {
                var s = Split(t.LChild, k);
                t.LChild = s.Item2;
                return new Tuple<Node, Node>(s.Item1, Update(t));
            }
            else
            {
                var s = Split(t.RChild, k - Count(t.LChild) - 1);
                t.RChild = s.Item1;
                return new Tuple<Node, Node>(Update(t), s.Item2);
            }
        }

        public static Node Remove(Node t, T v)
        {
            if (Find(t, v) == null) return t;
            return RemoveAt(t, LowerBound(t, v));
        }

        public static Node RemoveAt(Node t, long k)
        {
            var s = Split(t, k);
            var s2 = Split(s.Item2, 1);
            return Merge(s.Item1, s2.Item2);
        }

        public static bool Contains(Node t, T v)
        {
            return Find(t, v) != null;
        }

        public static Node Find(Node t, T v)
        {
            while (t != null)
            {
                var cmp = t.Value.CompareTo(v);
                if (cmp > 0) t = t.LChild;
                else if (cmp < 0) t = t.RChild;
                else break;
            }
            return t;
        }

        public static Node FindByIndex(Node t, long idx)
        {
            if (t == null) return null;

            var currentIdx = Count(t) - Count(t.RChild) - 1;
            while (t != null)
            {
                if (currentIdx == idx) return t;
                if (currentIdx > idx)
                {
                    t = t.LChild;
                    currentIdx -= (Count(t == null ? null : t.RChild) + 1);
                }
                else
                {
                    t = t.RChild;
                    currentIdx += (Count(t == null ? null : t.LChild) + 1);
                }
            }

            return null;
        }

        public static long UpperBound(Node t, T v)
        {
            var torg = t;
            if (t == null) return 0;

            var ret = long.MaxValue;
            var idx = Count(t) - Count(t.RChild) - 1;
            while (t != null)
            {
                var cmp = t.Value.CompareTo(v);

                if (cmp > 0)
                {
                    ret = Math.Min(ret, idx);
                    t = t.LChild;
                    idx -= (Count(t == null ? null : t.RChild) + 1);
                }
                else if (cmp <= 0)
                {
                    t = t.RChild;
                    idx += (Count(t == null ? null : t.LChild) + 1);
                }
            }
            return ret == long.MaxValue ? Count(torg) : ret;
        }

        public static long LowerBound(Node t, T v)
        {
            var torg = t;
            if (t == null) return 0;

            var idx = Count(t) - Count(t.RChild) - 1;
            var ret = long.MaxValue;
            while (t != null)
            {
                var cmp = t.Value.CompareTo(v);
                if (cmp >= 0)
                {
                    if (cmp == 0) ret = Math.Min(ret, idx);
                    t = t.LChild;
                    if (t == null) ret = Math.Min(ret, idx);
                    idx -= t == null ? 0 : (Count(t.RChild) + 1);
                }
                else if (cmp < 0)
                {
                    t = t.RChild;
                    idx += (Count(t == null ? null : t.LChild) + 1);
                    if (t == null) return idx;
                }
            }
            return ret == long.MaxValue ? Count(torg) : ret;
        }

        public static Node Insert(Node t, T v)
        {
            var ub = LowerBound(t, v);
            return InsertByIdx(t, ub, v);
        }

        static Node InsertByIdx(Node t, long k, T v)
        {
            var s = Split(t, k);
            return Merge(Merge(s.Item1, new Node(v)), s.Item2);
        }

        public static IEnumerable<T> Enumerate(Node t)
        {
            var ret = new List<T>();
            Enumerate(t, ret);
            return ret;
        }

        static void Enumerate(Node t, List<T> ret)
        {
            if (t == null) return;
            Enumerate(t.LChild, ret);
            ret.Add(t.Value);
            Enumerate(t.RChild, ret);
        }
    }
    #endregion


}