using System;
using System.Text;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
using static System.Console;
using static System.Math;
using System.Diagnostics;

namespace AtCoder
{
    public class Program
    {
        public static void Main(string[] args)
        {
            new Program().Solve(new ConsoleInput(Console.In, ' '));
        }

        public void Solve(ConsoleInput cin)
        {
            //ここに記述
            //データはストリームによて読み込まれており、' 'によって分割されている場合はキュー型のリストに蓄積れる
            // ' 'によって区切られていない場合、次の行を読み込むようになるので、そのまま記述してよい
            //var = cin.ReadInt; イント型

            var n = cin.ReadInt;
            var q = cin.ReadInt;
            var s = cin.Read;

            int[] a = new int[n];
            for (int i = 0; i < n; i++) a[i] = 1;

            for(int i = 0; i < q; i++)
            {
                string t = cin.Read;
                string d = cin.Read;

                for(int j = 0; j < n; j++)
                {
                    if(s[j] == t[0] && a[j] > 0)
                    {                    
                        if (d[0] == 'R' && j != n - 1) {
                            if (a[j + 1] > 0) a[j + 1] = a[j] + a[j + 1];
                            else a[j + 1] = a[j];                       
                        } 
                        else if (d[0] == 'L' && j != 0)
                        {
                            if (a[j - 1] > 0) a[j - 1] = a[j] + a[j - 1];
                            else a[j - 1] = a[j];
                        }

                        a[j] = -1;
                    }
                }
            }

            int answer = 0;

            for(int i = 0; i < n; i++)
            {
                if (a[i] > 0) answer += a[i];
            }

            WriteLine(answer);

        }

        public class ConsoleInput
        {
            private readonly System.IO.TextReader _stream;
            private char _separator = ' ';
            private Queue<string> inputStream;
            public ConsoleInput(System.IO.TextReader stream, char separator = ' ')
            {
                this._separator = separator;
                this._stream = stream;
                inputStream = new Queue<string>();
            }
            public string Read
            {
                get
                {
                    if (inputStream.Count != 0) return inputStream.Dequeue();
                    string[] tmp = _stream.ReadLine().Split(_separator);
                    for (int i = 0; i < tmp.Length; ++i)
                        inputStream.Enqueue(tmp[i]);
                    return inputStream.Dequeue();
                }
            }
            public string ReadLine { get { return _stream.ReadLine(); } }
            public int ReadInt { get { return int.Parse(Read); } }
            public long ReadLong { get { return long.Parse(Read); } }
            public double ReadDouble { get { return double.Parse(Read); } }
            public string[] ReadStrArray(long N) { var ret = new string[N]; for (long i = 0; i < N; ++i) ret[i] = Read; return ret; }
            public int[] ReadIntArray(long N) { var ret = new int[N]; for (long i = 0; i < N; ++i) ret[i] = ReadInt; return ret; }
            public long[] ReadLongArray(long N) { var ret = new long[N]; for (long i = 0; i < N; ++i) ret[i] = ReadLong; return ret; }
        }
    }
}